To all you naughty jailbreakers out there: PwnageTool 2.0.2 has been released adding support for iPhone firmware 2.0.1. It also includes Cydia and Installer 4 beta.
You can download 2.0.2 by launching PwnageTool 2.0.1 and selecting "Check for updates" (command-U). You can also download it directly. More details are on the the iphone-dev team blog.