Assuming you want blue or white lights for the cluster, I would get them here:
SportsCarLEDs.com Instrument Panel LEDs Kit for the Porsche ® Carrera 996 & Boxster 986
Then, if you feel like changing all of the LEDs on your dash and accessory switches, read through this thread:
http://986forum.com/forums/diy-project-guides/36014-changing-color-climate-control-switch-back-lights.html
The cluster bulbs are easy. The others require you to solder at least at a decent level.