Found this cool little device on Kickstarter designed to easily interface real arcade controls with a multitude of computers and gaming systems including:
PS, PS2, PS3
Xbox
MAME
Virtual Pin
It can also be used as a general USB keyboard or joystick and works with Windows, Mac, Linux, Android, etc. It's already passed the funding goal and the price including world-wide shipping starts at £20 (approx $32). Check it out.