Questions about Jailbreaking

[The Red Comet]

I have a 16gb iPhone 3G, and I'm considering jailbreaking it. Is it possible for windows yet? I read somewhere that it's OSX only currently, but elsewhere that a windows version has been released.

What exactly does jailbreaking do, or allow me to do? What are its advantages? I've been looking around but I haven't found too much info on this. I'm probably not looking hard enough, though.

I have some bought apps and some apps with saved data that I really don't want to lose. If I jailbreak correctly, will the apps still be usable, and will the save data remain untouched?

Thanks.

[Four20]

You can go here for a jailbreaking guide

http://www.installerapps.com/jailbreak/

Jailbreaking will let you install unofficial 3rd party applications like the NES emulator and the quake demo.

we are still waiting for Installer to be released though. . .

[The Red Comet]

So how would jailbreaking affect my current apps and whatever data I have on my iPhone, like music? I don't want to lose the save files on some of my games.

[The Red Comet]

*bump* (Sorry about the doublepost)