Although, the DS has a GBA cartridge slot, right? So I think if you wanted, you could play Fire Red or Leaf Green on a DS. Although it's not the exact same game, these are the Generation III remakes of Red and Blue/Green so the storyline and Pokémon should be similar. However, I don't think you can trade when using a DS to play GBA games so it might be worth just getting an old GBA to play these games :) good luck!
