We at WPSauce are a big fans of emulators. I have been playing emulators since early 2003-2004 mainly SNES, Nintendo 64, Saturn and then moving on to Play Station games. Android users have had emulators available legally on the marketplace for ages now, apparently - they are being removed now (whoops!) - Windows Phone 7 marketplace guidelines do not allow emulators, no surprise here. But fear not, homebrew community already have three distinct working emulators for you to get your hands on.
