Nintendo-DS-Roms.com - Note: You need eMule to download NDS Roms, full RomSet, GST, Demos and Nukes.
For Playing NDS Games for FREE use one of the DStwo, DSONEi, R4i GOLD, R4i SDHC, AceKard 2i, M3i Zero, DSi compatible R4i or R4 SDHC ROM Flash Cards. Download NDS ROMs -> copy to microSD card -> slide that into a R4 DS adapter and play on any NDS console for free! DS Lite , DSi or even DSi XL consoles can play backups without a Mod-Chip! Buy HERE
Just this weekend reduced prices all R4i DS and R4 3DS cards + free shipping to UK, USA and WorldWide.
CoolRom.com - Guaranteed Downloads of Gameboy Color GBC roms Atari 2600 CPS1 & 2, Namco System 22, Neo Geo Pocket NES, SNES roms, Nintendo 64, Sega Genesis CD and Saturn Games. *Update - Now also GBA Games!
ROMNation.net - One of the largest romsites online. Special sections for MAME (Arcade) Roms, SNES (Super Nintendo) Roms, N64 (Nintendo 64) Roms, Sega Genesis Roms but also has GB NES GBC and many other roms ready for download. Some forced voting, but that is only for the Next Generation and current console systems.
DopeROMs.com - Over 90000 ROMs and 141 emulators for 91 systems. The lastest GBA ROMs, N64 ROMs, SNES ROMs, MAME ROMs, Sega Genesis ROMs, NES ROMs, GameBoy ROMs. Most downloads are free but Premier Membership has to be purchased to gain access to roms of systems such as SegaCD, 3DO, Saturn, and NeoGeoCD.
MarioGBAroms.com - Nice clean Mario rom website, with direct downloads for many of the most popular Mario ROMs and working emulators for all active ROMs. (GBA, N64, NDS, SNES)
PoKeMoN Rom Emulator - emu files for all systems including GBA, Nintendo DS & DSi, Wii / GC pokemon games
Pokemon Online Roms - direct download 100% up time links to all the classic GB/GBC and GBA Pokemon roms.
Files2Send.com - over 2500 roms and growing. Free - no registration. Separate file sections based on interest and popularity: such as Pokemon Roms, Mario Roms, Popular GBA roms, etc.
Final Fantasy Emu - download emulators for all Final Fantasy Advance and Tactics games from NES, GBA to Wii.
Gameboy Multicarts - Cartridges with compilation of GBA and NES roms . Up to 250 games on one cart!
(NOTE: These cartridges are Read Only and can not be erased like gba flash cards. Use them on GBA, SP or NDS)
Poke-Amph.com - Pokemon Roms for GB Advance.
ChinaEmu.org - Slow server in china that has the latest Nintendo DS and Gameboy Advance files. Download links are located on each rom page just above the Google search. (you don't have to search - just click on the link above it)
EmulatorWorld.com - Freeware rom files & Emulators for various consoles. Voting is NOT mandatory.