JCB, they have done an actual hack, not a work around that the USB stick was. The hack is unpatchable, the only way to prevent it is an actual hardware change.
They got the "killcode" I suppose you could call it, the number which goes into each bit of software to make the console think it is a Sony product. It works with PSP too because they work off the same code, so basically you can create any homebrew or rip any game, put the number into the right bit of code and it will work without any questions
BBC News - iPhone hacker publishes secret Sony PlayStation 3 key
All they have been able to do so far, and will be able to do, is release updates to find compromised consoles and ban them from any online games