OH (original hacker, yo!) George Hotz has posted the RC2 version of his iPhone 3GS jailbreak tool, purplera1n. Along with other improvements, the new version supports Vista, Windows 7, and supports 64-bit.
If any of the above interests you, and you're a responsible adult who understands the risks involved, hit the link below and check it out. Jarrrr!
[On the iPhone]