hay all i was thinking that is there a way i can load homebrew on my r4 card which will let me play n64 or gba roms on my ds????
N64 isnt going to happen, sorry. GBA roms can be run but you need a slot 2 ram expansion cart, like the EZ-Flash. Other emulators are available here but keep in mind that you're likely to be disappointed by most of them. Game compatability is less than perfect, others do not run games at full speed or lack sound.
No, N64 roms cannot and never will be playable on the DS. GBA roms require a ram expansion pack which the GBA Rom is loaded too. However it is possible to run NES, SNES, Sega Master System, Genesis, and other emulators and games on your DS. Go to the third link in my signature for the emulators and applications. NES - NESDS emulator - NES Folder - L and R buttons used for fastforward or rewind. SNES - SneMulDS emulator - SNES Folder - Many options so most roms can be utilized. Sega Master System - Sega Master System - Sega Master System Folder - Most Roms Work Genesis - JenesisDS - Genesis Folder - Most Roms Work