Pinball Life Terry has a good selection of commonly used items and his prices and service are excellent
Marco Specialties A good vendor that has a large selection of parts for most machines.
Repair Information  
Advanced Repair Center Currently repairing all Sega Game Boards from 1994 ( Daytona ) thru 2006 (Outrun 2)
Informations Sites  
MAME Offical Mame developers site.
Killer List of Video Games The complete database of video games.
Internet Pinball Database The complete database of pinball machines.
Atari Museum Gotta love his site. Have you ever heard of Atari?
Mameworld A wonderful mame site.
Mr. Pinball Classifieds Machines and Parts for sale.
Stern Pinball The world's last pinball manufacturer.
Pinball Hall of Fame If you are a pinball fan GO NOW!
Obviously, these are in no certain order. If you would like me to add your site please email me.