blog.iphone-dev.org | The man from DelMonte – He say Yes!:
There’s an app that’ll backup all of your jailbreak apps so that you don’t have to reinstall them all after the update, but I kinda wanna start from scratch.  Right now I can think of about 2 apps that I’ll re-install.  Well, maybe 3.

Crap.  It’s about 6, but it’ll still be easier for me to start from scratch.

Happy JailBreaking!