The industrious folks at iFixit have published extensive manuals for 24 popular game consoles, detailing over 200 repairs and modifications with step-by-step guides and photographs. You knew there was a reason you were keeping that broken Game Gear around.
Some of the consoles covered include:
Microsoft - Xbox - Xbox 360 and 360 S
Nintendo - Nintendo 64, GameCube, and Wii - Game Boy (Original), Advance, Micro, DS, DS Lite, DSi, and DSi XL
Sega - Dreamcast - Game Gear
Sony - PlayStation 1, 2, 3, and 3 Slim - PSP 1000, 2000, 3000, and Go