what is jailbrake for an iphone?

Hacking it so to speak with functions you prefer that are not part of the original OS, this does not apply to webapps. Also, some jailbird phones are being used in countries other than Apple’s intended market, and internationally with carriers other than AT & T.

Jailbrake allows you to modify your iPhone software beyond the extent allowed by apple. Be warned, however, it violates your warranty.

Also asked a dozen times. SEARCH!

http://www.fluther.com/disc/4985/what-is-jailbreak-for-ipod-touch/
http://www.fluther.com/disc/7736/what-is-jailbreak-and-how-can-i-get-the-piano-for/