Trying to get homebrew running on your PSP? Want to add a screen light to your Game Boy? Trying to figure out how to work your GP2X? By popular demand, discuss it in here! (This forum is for pre-built handhelds, NOT custom made portables!)
if you're asking if you can use it as a screen (only) then it can be..
if you're asking if you can use it as a screen (a touch screen) then it's impossible.
You can remove the top screen of the DS using a simple override by bridging two pins, thereby having a single screen DS for playing gameboy advance games.
I am a case modder trying to be a portablizer. Will get there one day.
No, unless you want to figure out the pinout and make a controller for it that can interface with the semianalogous interface the gameboy normally uses.