The iPhone Dev team released a new tool called QuickPwn that jailbreaks an iPhone more quickly without requiring a full restore.
The released QuickPwn version is still a development version and only available for the Windows platform right now.
Currently QuickPwn requires your iPhone to be running version 2.0.1 of the iPhone/iPod firmware. A full release version of QuickPwn is expected in a couple of weeks.
More details and download of QuickPwn available on the iPhone Dev Team site.

The latest full PwnageTool 2.0.2 jailbreaks the iPhone OS 2.0.1 and unlocks old iPhones. The hacker team is still working on the iPhone 3G unlock.

Update:
QuickPWN GUI version 1.0 has been released. It has a better GUI, allows jailbreaking of 2.0.2 firmware, and you just need to choose your device from a sleek graphic screen and the firmware in order to use it. The new download is available here.