iPhone 3GS owners who would like to jailbreak and/or unlock their new devices will have to wait a little bit longer. The iPhone Dev-Team has already jailbroken the iPhone 3GS running OS 3.0 but they are postponing the public release.
The cat and mouse game is never simple. Dev-Team is worried that releasing a jailbreak now will give Apple too much information. The iPhone OS 3.0.1 release is surely coming soon, and if Apple corrects the bug Dev-Team is exploiting then future iPhone 3GS users will not be able to hack their phones.