from gizmodo.com

After some delays, the iPhone Pwnage tool—which is used to flash your iPhone with hacked firmware that will allow you to run any application, use it unlocked in any compatible cellphone network, and basically do whatever you want do to with it, is now available for download. I have been testing this and previous versions for a few weeks now and it works well, but you will need a 2.0 version of the iPhone firmware to try the latest and greatest.