Why? There are plenty of GOOD tutorials on doing it in the forums and on the site.
1) Open Case
2) Solder 2 sets of 2 points (You may have to run a wire to the d0, depending on the version)
3) Find a way of getting a flashing program onto your Xbox (Have someone with a modded Xbox put it on a card, take out the drive and put it on from a computer, etc)
4) Flash the onboard bios
5) Reboot and hope you did everything correctly
Again, this isn't the COMPLETE way of doing it. There ARE complete, easy guides to follow on this site. Check the TSOP flashing forum.