psp:
-it more of a teenager portable
-the speaker is pretty loud
-graphic is more beatiful than ds
-cool games
-a lot of application that can be downloaded(dont be stupid and download fake/dangerous application that will brick your psp)
higher quality graphic and sound

ds:
-able to play at daytime with the sun shining on the screen
-games are more fun but lame

personally i like psp more scince it more cool after all i think ds is for kids(no offense to adult/teenage ds lover)