There's got to be a way to do this legally. Its the way that the internet was made to play retro video games.
Update:I broke down and sent my IP lawyer an email and instructions to give me some legal advice on what to do here. Its freakin expensive, but if you feel that I may be doing something illegal still, Its still cheaper than a lawsuit.
Update Update: It may be legal if I allow users to upload games. http://www.law.cornell.edu/uscode/html/uscode17/usc_sec_17_00000512----000-.html
Update 3: Actually, according to that page, it may be legal right now.