j/w why isn't that legal, since he owns the game he has all rights to it as long as he doesn't sell it to anyone, its like a backup. Same thing with NDS emu roms if you have the real game then its legal to download a rom for a emu.
One of my friends made one using VBasic & java. Most likely you can find a free test script and I know where you can get a free arcade website that has 200+ games http://forums.xisto.com/no_longer_exists/ or here 500 games or buy it for 20$ and get 5000 games http://www.hugedomains.com/domain_profile.cfm?d=agaresmedia&e=com