Most people do not use Nero because they don't have the full fledged suite and you have to pay for it (unless you download it illegally via a Torrent). I paid about 70 dollars for the entire suite including Nero Express, Nero Recode, and Nero Vision (for encoding DVDs from AVI). I use these programs a lot so I thought it was worth it to buy the software.
You can find it here:
Nero - Buy nero products online
Or perhaps you already have it, or you have downloaded a torrent of it and didn't even realize you had a nice easy way to make movies for your iPad.
I tried Handbrake at first, but got fed up with errors, how long it took, and the process of having to individually add movies to the queue instead of bulk selecting them.
So the first thing we will do is start up Nero Recode. You will see this screen.
To encode AVI/MPEG etc files choose "Recode DVDs and Videos to Nero Digital". Next you will see the following screen.
Once you get to this screen, you are going to choose Apple iPod from the Profile Category drop down box and either Fast or High Quality (I always choose fast and don't notice a difference to be honest, but NumbLock has done interesting tests that suggest you might notice a difference in quality depending on the source). The profile iPod/iPhone AVC should automatically be chosen when you choose Apple iPod from the Profile Category drop down but if it isn't, go ahead and select it.
Next thing you are going to do is drag and drop the AVI or other movie files you want to encode into the box in the middle. Alternatively you can choose the Import Files button and navigate to the folder they are located and select or highlight multiple selections and add them.
In this example I am going to encode seasons 1 through 8 of the TV show Scrubs for my wife...so I dragged all of the episodes into the box. It took about 30 seconds of time for it to put them all in there. You will see what you see in the screen shot below.
In the content box you will see the individual files, their length, the NEW (not source) file size, and a video quality slider. I usually leave the quality slider where it is. Honestly I am looking to be entertained with my iPad, not set a new record for video quality. I would rather sacrifice some video quality in order to store more movies on my device when I travel. If I wanted to watch movies in high definition I would be doing so on my Playstation 3 Blu-Ray and my 60" HDTV and surround sound. That kind of quality is unnecessary for me when I am on an airplane for example.
That's all you really have to mess with on this page, is how much quality you want. I always leave it default. If you increase or decrease the quality slider you will see the new estimated output file size appear after a few seconds.
So now you're going to hit next and you will see this screen.
Here you have basically one of two options. If you're like me, I save all of my iPad formatted movies on a different external drive than the one I work on them on...so I choose my destination from the Destination Drop Down Menu as "Hard Disk Folder" and then I pick a folder. In this case I have them being saved to c:\Downloads.
Alternatively, if your iPad is plugged in, you can choose to burn them directly to the iPad. Honestly, I don't recommend this only because it could get messy, you could have sync issues, etc. So I just suggest putting them to a hard disk folder, organizing how you want them, adding them to the iTunes library and going from there. It sounds more indirect but you have much more control over the sync process in the future.
Lastly, you can burn them to a DVD if you want.
So choose hard disk folder, then pick the folder, then hit Burn.
That's it! You're done! You'll see the following screen, and it will give you an ever changing estimation on how long it will take to burn all of the episodes, in addition to a log of which one it's working on, how many it has left, etc.
If you hit the more button you can choose the priority for this task so it completes quicker. I usually set a large amount to go over night. It will take a while for it to adjust to tell you the true time remaining. And of course if you start doing a bunch of other things that require the CPU, like installing updates, that will change. As you see here it says 840 minutes remaining (that's for 167 episodes give or take) but just since submitting this thread the estimation is already down to 700 minutes.