Probably no better than 320x234 for this size an LCD, but for $50 brand new, it's hard to pass up! Certainly don't expect it to be the same quality and rez as the Sony PSOne panel (can be mod'ed to display 640x480 and take VGA input -- the real Sony-branded one, not the knockoffs), but it doesn't cost as much either.
http://www.amazon.com/exec/obidos/ASIN/B00006DY1K/prime1-20?creative=327641&camp=14573&link_code=as1
http://www.amazon.com/exec/obidos/ASIN/B00006DY1K/prime1-20?creative=327641&camp=14573&link_code=as1