Adding a new board to the IDE?

What do I have to modify to add a new variant to the IDE? I'm pretty sure I've figured out how to port the bootloader, core, and libraries over but I'm not sure how to go about modding the IDE.

Add an entry to boards.txt while the IDE is NOT running.

Start from here
http://arduino.cc/blog/?p=416
and follow the links

Eberhard