http://www.xboxhacker.net/

Congratulations to everyone who has been working hard on this project here in the forums and elsewhere. Nice job! I am glad that XboxHacker.Net has been able to serve a place in this community once again. XBH does not advocate piracy and we hope that these advances will assist us on the way towards our end goal: custom software for the Xbox 360.

A little more about the hack: it's a firmware hack that circumvents some disc security mechanisms. Executables must still be signed; the hack does not allow code that hasn't been signed by Microsoft to run, so no custom software or Linux yet. The door has now been cracked open though.

For those looking for a canned release of the firmware to pirate-and-go, this won't be the place to get it