Veja minha resposta para Jailbreaking my iPod touch :
There are a couple of different programs out there for jail breaking the iDevices, all with their different processes, pros and cons
PwnageTool
Version 3.1.4, Mac OS X
PwnageTool creates a custom, jailbroken firmware to restore to your iPod. This is only really good if you have an iPhone and don't want to upgrade the baseband in order to do a carrier unlock, or if you want to reset your device and erase everything from it.
Latest compatible firmware: 3.1.2
Compatible devices:
- iPhone
- iPhone 3G
- iPod touch
- iPod touch 2Gen1
1Note: The 2nd gen iPod touch must be already jailbroken in order to accept the custom firmware. As a work around, install (and jailbreak) using 3.1, then use PwnageTool to update to the latest firmware
Blackra1n
Mac OS X, Windows
Blackra1n is a new tool that claims to jailbreak your device in 30 seconds. It is very similar to the redsn0w or Quickpwn of yesteryear. It works by connecting an un-jailbroken device in and run the program. It will take like 5 seconds and reboot the device, and it is jailbroken. I have used this for my iPod touch and I am quite impressed by it.
Latest compatible firmware: 3.1.2
Compatible devices:
- iPhone
- iPhone 3G
- iPhone 3GS
- iPod touch
- iPod touch 2Gen
- iPod touch 3Gen1
1Note: Blackra1n is a tethered jailbreak for the third generation iPod touch. This means that every time you restart your device (which isn't really that often for most people) you have to connect it back to a computer and run Blackra1n again.