RedSn0w is an easy to use, multi-platform, multi-device jailbreaking and unlocking (iPhone 2G only) tool from DevTeam. It supports firmware 3.0 and iPhone 2G (original iPhone), the iPhone 3G (but not the 3GS) and also the iPod touch (first and second generation):
iPhone 3G – only jailbreak, use only with official unlocked iPhones (UPDATE: unlock is avaliable)
iPod Touch – jailbreak
iPod Touch 2G – jailbreak
iPod Touch 3GS – not supported (UPDATE: is supported by version 0.8)
Currently it is available for Windows and Mac OS X. The tool works just like QuickPwn. If you want to build custom firmware files with more flexibility it is suggested that you use PwnageTool on Mac OS X.
GOLDEN RULE: If you are using a 3G iPhone with yellowsn0w and rely on yellowsn0w to obtain cellular service, then you should NOT use redsn0w right now. Ultrasn0w (the 3G carrier unlock) is not included with this release and therefore your baseband will be locked and unable to use an operator other than the official one it was bought for. UltraSn0w will be released via APT (cydia and icy) soon. If you have an original iPhone (1st generation) then 3.0 carrier unlock works with this redsn0w release.
Yellowsn0w in its current form will NOT work with the baseband version that is present in the 3.0 update, you will need Ultrasn0w, which will be released sometime soon (update: released), Ultrasn0w will work with all iPhone 3G models (but not 3GS), even ones that were previously unlockable, Ultrasn0w will be released via APT (this means you will be able to get it via Cydia or Icy).
Please read all parts of this post before downloading and using these tools.
Read items 1, 2 and 3 again and again.
At the bottom of this post are the bittorrent files for the latest version of redsn0w.
This app is suitable for the recent 3.0 release
redsn0w will NOT work for the iPhone 3GS.
redsn0w WILL work for Original iPhone (1st Generation), Original iPod touch, iPod touch 2G and the iPhone 3G (not the iPhone 3GS).
To use redsn0w simply upgrade the device in iTunes to firmware version 3.0 and run redsn0w to activate and jailbreak the device (and if you are using an original iPhone 2G, it will unlock it too!)
Sn0wBreeze 2.9.3(pwnagetool for windows, supports tethered jailbreak of iOS 5.1 for iPhone 4, iPhone 3GS, iPod Touch 3G, iPod Touch 4G, iPad; untethered for iPhone 3GS with old bootrom; untethered for iOS 5.0.1, iOS 4, iOS 3 supports Apple TV 2G)
Sn0wBreeze 2.8b11(pwnagetool for windows, supports iOS 5, iOS 5.0.1, tethered jailbreak for iPhone 4, iPhone 3GS, iPod Touch 3G, iPod Touch 4G, iPad, Apple TV 2G; untethered for iPhone 3GS with old bootrom)
Current version is ultrasn0w 1.2.3, download in Cydia (unlock for iPhone 4, iPhone 3GS, iPhone 3G, firmwares 3.0-4.3.3; it supports basebands 01.59.00, 04.26.08, 05.11.07, 05.12.01, 05.13.04, 06.15.00)