Can someone give me an advice about jailbreak? Is it good to iPad and how useful is that? I heard some people say that it's illegal, while others say that it's legal, so which is right?

Hello and welcome to the forum. Good to see you and I hope you enjoy your visits.

To start learning about jail breaking, have a look at this thread: http://www.ipadforums.net/ipad-hacki...ed-2011-a.html

Then, if you are still interested, have a look at this thread to see if your iPad is jail breakable: Jailbreaking Methods for the iPad

Finally, if you've jail broken your iPad, this thread lists the favored member tweaks (and shows you what a jail broken iPad can really do): Ultimate List of Jailbreak Tweaks

If you still need more info, grab a snack and a beverage of your choice and start reading the posts in the Hacking section here in this forum. It is just chock full of information on jail breaking (pros, cons, issues, joys, etc).

Hope this helps.

Marilyn

P.S. And, since you talk about a jail broken iPad, I've taken the liberty of moving your post over to the Hacking section. Thanks for your understanding.