The iPhone Dev-team, a group of hackers who have previously created many unlocking and jailbreaking applications for previous iPhone models, says that the iPhone 3GS jailbreak is ready, but they are waiting the 3GS customer base to reach a critical mass before they unleash the new software. According to them, releasing it too soon would help apple circumvent their hack, which would in turn make the process more complicated for users because the iPhone Dev-Team would need to churn several version of the jailbreak software. At the moment, the team wants to wait until OS 3.0.1 so you’ll have to be patient.
Related: iPhone 3.0 Jailbreak Is Ready
George Hotz has released an alternate Jailbreak for the iPhone 3GS, called Purplera1n.