Nes
(Too many links to post here, i'll post the important ones, you can find Nes docs easy anyway)
NES nocash docs
6502 reference
Super Nintendo
Programming the 65816 Snes programming tutorial
Snes graphics documentation
GB/GBA/DS
GBA & DS NO$ Docs GBATEK
GBA_11.pdf (application/pdf Object)
Tonc: Whirlwind Tour of ARM Assembly
ARM ASSEMBLER PROGRAMMING; tutorial, resources, and examples
ARM7TDMI Tech manual
ARM7TDMI data sheet
CowBite Virtual Harware Spec
GBA Game development
GB/GBC Specs
Game dev
ARM Instruction Formats and Timings
Playstation 1
Everything you ever wanted.. (html)
Everything you ever wanted.. (pdf)
Playstation 2
Inside the Playstation 2: PS2 Architecture, Graphics Rendering and Programming
Procedural Rendering on Playstation
An Introduction to PS2DEV « Lukasz.dk
PlayStation 2 Architecture (pdf) (takes ages to load)
A Technical Overview of the Emotion Engine
PS2 Basics
PS2IOP
PS2BMP1.pdf (application/pdf Object)
Win32 PS2 Dev. Intro
Downloads - GSHI
MIPS Assembly
VPU Thesis (pdf)
Nintendo 64
RCP64, Nintendo 64 Machine
Nintendo 64 Specifications
http://infrid.com/rcp64/docfiles/n64maps.txt
Nintendo 64 Tech
Nintendo64 Technical Information...
Misc
Sanity Warning
HUGE emulator list and sources etc
NO$FUN (All NO$ docs)
Peace