The following is a list of the current methods which can be used to jailbreak your iPad:

iPad3 (The New iPad, 3rd Generation)
There is no jailbreak for the iPad3 yet. Stay tuned to the forums for news as it is announced! - Official iPad3 Jailbreak Thread

iPad2
Absinthe - Firmware 5.0.1 via uber-complex jailbreak payload, available from greenpois0n.com Follow our tutorial here - TUTORIAL - Jailbreak the iPad2 on 5.0.1 with Absinthe

jailbreakme.com - Firmware 4.3.3 via jailbreak payload, available from Jailbreakme - Note - You must visit this site using Mobile Safari on your iPad2!

You CANNOT jailbreak any other version of IOS on the iPad2 except those listed above. No exceptions!

iPad1
The iPad1 (A4) device is pwned for life, so jailbreaking is fairly trivial. At worst, you will usually find a tethered jailbreak for the latest version of IOS!

redsn0w 0.9.11 - Windows and OSX - Firmware 5.1.1, 5.1, 5.0.1, 5.0,, 4.3.3, 4.2.1, and 3.2.2 via jailbreak payload, available from Dev-Team Blog
We have a step-by-step redsn0w tutorial here - TUTORIAL - Jailbreak iPad1 on IOS5 using redsn0w

sn0wbreeze 2.9.3 - Windows Only - 5.1, 5.0.1, 4.3.3, 4.2.1, 3.2.2, 3.2.1, and 3.2 via custom firmware, available from iH8sn0w.com
We have a step-by-step sn0wbreeze tutorial here - TUTORIAL - Jailbreak iPad1 with sn0wbreeze

ac1dsn0w - OSX Only - Firmware 5.0.1, and 5.0 via jailbreak payload, available from Pwn Dev-Team
See our tutorial for ac1dsn0w here - TUTORIAL - Jailbreak iPad1 IOS5 (tethered) using ac1dsn0w

Pwnage Tool 5.1 & 4.3.3 - OSX Only - Firmware 5.0.1 and 4.3.3 via custom firmware, available from Dev-Team Blog
Here is Max's pwnage tutorial - TUTORIAL - Jailbreak with Pwnagetool for Mac

jailbreakme.com - Firmware 4.3.3, 4.3.2, 4.3,1, 4.3 via jailbreak payload, available from Jailbreakme - Note - You must visit this site using Mobile Safari on your iPad1!

Older methods for older firmware:
greenpois0n RC6.1 - Windows & OSX - Firmware 4.2.1
greenpois0n RC4 - Windows & OSX - Firmware 3.2.2
limera1n - Windows & OSX - Firmware 3.2.2 - see the old limera1n thread
Jailbreakme.com (2.0) - iPad via Mobile Safari - Firmware 3.2.1
Spirit for Windows, Linux, OSX - Firmware 3.2

Colour Key:
GREEN - indicates the newest IOS version which can be jailbroken and untethered with this tool.
ORANGE - indicates the newest IOS version which can be jailbroken but remains tethered to the tool.

What's the difference between an untethered and a tethered jailbreak?
An untethered jailbreak means you can reboot your device at any time and the jailbreak will continue to function as expected. Ideally, you want to always be running an untethered jailbreak.

However, from time to time we have to live with a tethered jailbreak as the only option for a particular device and IOS version until such time as an exploit to untether it is found (untethering a jailbreak is an order of magnitude more complex than producing the tethered one).
If a jailbreak is tethered then you must reboot your device whilst it is connected, or tethered, to your PC which is running the program you used to jailbreak it originally (or a reboot tool provided with the jailbreak, such as iBooty from sn0wbreeze).
If you don't tethered boot your device, one of two things will happen. Either the device will hang at the Apple logo if you have mobile substrate or anything else installed which hooks into the kernel of the OS. In this situation you will need to wait until you can connect your device to your PC and boot it properly in a tethered state. Or, the device will boot to stock IOS but none of your JB apps will work. You may also not be able to use some stock apps, such as Safari, which most JB's move to a different part of the disk as part of their original installation.
In the case of the iPad, being tethered can be a pain, although the number of times you actually have to reboot an iPad can be few and far between so you could consider it better than a tethered jailbreak on an iPhone, which is no fun at all!
I lived with a tethered jailbreak on iPad 4.2.1 for several months last year and it really wasn't difficult for me, but YMMV.

What's the difference between a jailbreak that uses a payload versus one that creates a custom firmware?
redsn0w, greenpois0n, and limera1n all deliver the jailbreak as payload via a ramdisk on top of your currently installed IOS system. This means that these methods will leave your current applications and settings intact without the need to re-sync with iTunes.
jailbreakme.com exploits a userland bug on the device and delivers it's payload straight onto the iPad vai a malformed PDF through Mobile Safari.

It should be possible to complete a jailbreak using and of these payload methods in literally a few minutes.

pwnage and sn0wbreeze jailbreaks both cook a complete custom firmware file which must then be restored onto your device. This means you have a clean fresh installation of IOS + the jailbreak when you finish. You therefore won't have any of your previous applications or settings unless you then connect to iTunes and restore from backup and re-sync your files. These methods take a bit longer. You will need to download a stock firmware file to feed into the tool and then, once cooked, install it on your device via iTunes. In order for these types of jailbreak to work the tool must be able to put your device into what is known as a "pwned DFU" mode so that it is fooled into accepting the installation of a firmware which did not come from Apple.

Which method should I use?
Of course it's all down to personal choice!

If your device and IOS version is susceptible to the jailbreakme.com 3.0 exploit, most users will find this the easies and most convenient method. Simply fire up Mobile Safari on your iPad and visit jailbreakme.com, and follow the instructions You will be jailbroken normally within a minute.

Next in order, and assuming you have your device set up the way you want on the correct version of IOS, then you will probably prefer any of the other jailbreak payload tools, such as redsn0w, since these will install very quickly and leave your apps intact. It is possible to complete a redsn0w jailbreak in less than 15 minutes as long as you have the correct firmware downloaded to your local disk.

If on the other hand you need to upgrade IOS to a later version in order to jailbreak, or you are the sort of person that likes to start clean and fresh from time to time, one of the custom firmware jailbreaks, such as pwnage or sn0wbreeze, may suit you better... I recently used sn0wbreeze to jailbreak my 64GB iPad1 and then entire process took around 4 hours from start to finish (this included completely restoring my 64GB of files and settings from iTunes backup)

Happy Jailbreaking my hacker friends.

Managed to access this thread via your sig, thanx for the info :-)

Hi
My ipad 1 is version 4.2 and with jb
I have alot of app that installed from my jb
How can i prevent lossing my app from jb after update my device to 4.3
Already before i update my device from 3.2.2 to 3.4 without lossing

Thanx ,

3.2.2 to 4.2 *
Am correcting my mistake above

Excellent overview! I didn't know the difference between payload and custom firmware, but noted the difference between redsn0w and sn0wbreeze as I switched from one to the other. Now I know.

One difference between the two is that using sn0wbreeze 2.5 allows for an easy way to enable multitouch gestures, where redsn0w requires editing of system files using iFile or equivalent. At least, that's my understanding. What's especially fun is watching stock iPad owners marvel when I use multitouch instead of the home button. A short-lived novelty, but fun nonetheless.

Originally Posted by AWolfOutWest

One difference between the two is that using sn0wbreeze 2.5 allows for an easy way to enable multitouch gestures, where redsn0w requires editing of system files using iFile or equivalent. At least, that's my understanding. What's especially fun is watching stock iPad owners marvel when I use multitouch instead of the home button. A short-lived novelty, but fun nonetheless.

I'll update the post when I get 5 mins to explain that a bit better. An advantage of snowb and pwnage is how you can add your own bundles and enable options. Cheers.
Totally agree about gestures. Can't quite work out how much I like them, but I do like them!

Hi
My ipad 1 is version 4.2 and with jb
I have alot of app that installed from my jb
How can i prevent lossing my app from jb after update my device to 4.3
Already before i update my device from 3.2.2 to 4.2 without lossing

Thanx ,

Originally Posted by Hashem

Hi
My ipad 1 is version 4.2 and with jb
I have alot of app that installed from my jb
How can i prevent lossing my app from jb after update my device to 4.3
Already before i update my device from 3.2.2 to 4.2 without lossing

Thanx ,

You should wait for jailbreak to be released for 4.3 then only you should update.
Backup your device to iTunes, then update your device with new OS. Run jailbreak connect your device to iTunes and do a restore.

Sent from my iPad 2 using Tapatalk

Originally Posted by Bluray

You should wait for jailbreak to be released for 4.3 then only you should update.
Backup your device to iTunes, then update your device with new OS. Run jailbreak connect your device to iTunes and do a restore.

Sent from my iPad 2 using Tapatalk

The jailbreak for 4.3.1 has been out for a couple of weeks now on all devices except iPad2, so there is no reason to wait as the poster stated it was an iPad1.

Originally Posted by Hashem

Hi
My ipad 1 is version 4.2 and with jb
I have alot of app that installed from my jb
How can i prevent lossing my app from jb after update my device to 4.3
Already before i update my device from 3.2.2 to 4.2 without lossing

Thanx ,

If I understand you correctly and you want to save your Cydia apps and settings, you can look into some of the app / package backup solutions in Cydia. My favourite is pkgbackup. This backs up a list of your installed packages as well as the settings for each one so they can be restored on a freshly jailbroken system. Google pkgbackup for more details.