Saw this article on SecurityFocus. Very interesting/fun reading:
Hacker Penetrates T-Mobile Systems. The article linked from this one about the guy selling Microsoft source code for $20 is pretty interesting too. I wonder how long it would have taken them to find out about the leak if the guy hadn't tried to sell the info? I'm sure there are a lot smarter people with this kind of access that don't.
Lessons to learn: If you hack a computer system, don't try to sell the information. If you have to brag about it, use a new, anonymous account each time, and never, ever, agree to meet up with people through their "proxy server" to prove it. And if you sell the source code to one guy and he "loses it"... Don't do it again. LOL. Just enjoy Paris Hilton's phonecam pics.