Yes all Gameboy Advanced games will play in the DS, there is a pull out cartridge thing on the bottom of the DS where you put the Gameboy Advanced cartridges in.
Very good handheld system...we own 2 and even I still play!!!
:-D
Good news! The DS is compatible with all Gameboy Advance games (cartridges for the GBA and GBA SP are identical). No adapter is needed; there is a separate cartridge slot on the bottom of the DS which accepts Gameboy Advance games.