PocketNES would probably be your best bet really. 9.99 recently came out, but I'd stick with 9.98 as the new version introduced some odd screwups. Don't bother with the GBAMP version or the pocketnes_compy version, as they were made for the GBAMP. The former uses a FAT library to bring portions of the NES game into the GBA's RAM as it needs them, while the latter compresses roms that are up to 256 kb in size (uncompressed) to a point that the emulator + rom can fit into the GBA's 256 kb of RAM. As you can run large GBA binaries on your M3, these two versions are obsolete for you.
You could also try HVCA, although I've personally only used it for playing NSF files on the GBA. Note that this is the only way to play NSF files on the GBA without using Pogoshell. Installation instructions are at http://wiki.pocketheaven.com/Hvca
Also note that HVCA will let you play .fds files (Japanese NES games, stands for Famicom Disk System) if you're interested in that.
EDIT: if you really want to partially compress your games, without losing features like pocketnes_compy does, then you could try Kuwanger's fork called "PocketNES...k" which lets you compress NES roms somewhat. I personally don't use this, as the amount of space saved isn't very noticeable, but you might find it useful.
Bookmarks