I doesn't work for a lot of games and the programers didn't map the keys to keyboards and mice. But some do use it. I dunno, try it out, get a ps2 to usb coverter for you mouse and keyboard if they are not USB already and try it out.
I've only been able to use a mouse with the Armored Core series of games. And then only to design a logo. I think the Evercrack game for PS2 uses the keyboard for chatting.
Make it idiotproof, and they'll make better idiots.