Let me try to explain; Jailbreak doesnt mean Unlock, or a way to install cracked apps; is just a matter to have your full rights on your phone! So you can get things that Apple will never give you, like access to the phone OS, which is unix (yes, its unix) as root. You can install tons of open source applications and games that are being ported to the iphone; you can get them using Cydia or Installer; example of some apps i like are: Apache server with PHP5, Netatalk server (An app that runs in the background, after installed, you give your iphone the ability to act as any other macintosh on your network, because its an Open Source implementation of the AFP protocol, its auto discovered), OpenSSH server (that you can use to connect to your iphone with ssh. sftp, etc), Cycorder for video recording with audio, 3Proxy (a proxy server that you can use for share your internet with other devices), you have Veency which is a nice vnc server for your iphone, etc; all free apps. And i’m talking about the latest firmware, 2.1, all these are 100% compatible. And for doing this, you don’t need to install any cracked application, just open the firmware to give you root access and install Cydia at least; processes that are automatically made by PwnageTool in simple easy steps, and after this, if you want it back to jail, you only need to restore your iphone with itunes again.