According to Steve Job, all iPad 3G is unlocked. You can use it with any gsm carrier. Check out this YouTube that I find from another post
http://www.youtube.com/watch?v=ToXqD...eature=related
Even thought I had he 3G version, I had never tried with another sim(dont have one laying around) and don't kow if it really work. So, take it with your own risk! =p