the ez flash 3 in 1 for the ds lite (they make a ds fat version)
but this can play gba roms, it works as a rumble pack and it allows you to ruun the ds opera browser if you have the rom which can be easily downloaded.
HERE is the cheapest website to get one this link will bring you to a black ds lite version they also have the white ds lite version here for the same price and they have the ds fat version somewhere i never looked for it
this website is cheap with free shipping (its actually a penny but go figure) i have ordered from here many times so i can tell you its safe and also i just ordered this same product from here