Here are download links for the latest versions of software for iPhone, iPod Touch and iPad jailbreaking, activating and unlocking:
evasi0n | RedSn0w | Sn0wBreeze | PwnageTool | Absinthe |GreenPois0n | iReb | iBooty | iFaith | UltraSn0w | LimeRa1n | Spirit | BlackRa1n | BlackSn0w | PurpleRa1n
For iOS 4.0, iOS 4.0.1 and
iFaith 1.4.2 (Windows tool that will save SHSH keys for your current installed iOS)
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)
You can download older software versions