With the dreamcast you have to get a VGA box (i had a blaze one that worked well), it increases the resolution to 640 i think but isnt compatable with all games, code veronica is one that spring to mind, did look fantastic on msr ect though, output is standard VGA d-sub. I'm not sure how difficult they are to find now, very i expect, as nokkonwub says for the PS2 you need a non machine specific converer box which can be expensive and generally poor quality, best bet imo is a vivo graphics or TV card or get a new TFT with s-video imput as standard.