The first jailbreaking application tool called purplera1n for the iPhone 3GS is now available. It will only allow the installation of unofficial third-party applications, but will not unlock the iPhone 3GS.
Check out http://purplera1n.com/ now!
George Hotz, a longtime Apple hacker, has released for the general public a tool that enables Windows users (not version 7) to jailbreak the iPhone 3GS, and older models running the 3.0 software update. The tool does not perform a carrier unlock, which would allow users to use sim cards from other wireless providers than the one they bought the device from.
However, the purplera1n jailbreak will free your iPhone from the limitations imposed on it by AT&T and Apple. After jailbreaking, a user will be able to customize the iPhone with home-screen wallpapers and third-party ringtones. But the biggest advantage of jailbreaking is the support of unapproved apps such as iBlackList (blacklists and whitelists for contacts) and many others.
But Hotz is not the usual suspect when it comes to releasing jailbreaking tools for the iPhone. By now, the iPhone Dev Team have been steadily releasing jailbreaking tools for the public. But the team has hesitated to release one for the iPhone 3GS because of the imminent release of the iPhone 3.1 software update (which would break any hacks the team has achieved).