Ladies and gentlemen, it's finally happened; the iPhone 3GS has been jailbroken. The first pictures were posted here, and it didn't take long for excitement over the achievement to spread throughout the Internet.
Update:iPhone 3G S Jailbreak delayed by iPhone Dev Team.
Jailbreaking is a term that refers to hacking a phone in order to gain access to its Unix filesystem. When a handset has been jailbroken its owner has access to parts of the phone that are normally unavailable. This allows owners to unlock the handset for use with another mobile carrier, as well as tinker around and make custom programs for their smartphone. Jailbreaking an iPhone voids the warranty, so it's really the sort of thing you should only get up to if you know exactly what you're doing.
George Hotz, aka “geohot”, knew exactly what he was doing when he started trying to jailbreak his iPhone 3GS. That's because, in addition to being the first person to unlock a 3GS, he was also the first person to unlock an original iPhone. He and the other boys at Chronic Dev have been hard at work since the release of the 3GS, and it seems their efforts have finally paid off.
One jailbroken iPhone is just the prelude to many more. Expect to see a complete guide to unlocking the 3GS appear within the next few days, possibly weeks. Congratulations, geohot and friends!