here is were you can get an atari emulator: http://www.emulator-zone.com/doc.php/a2600/
and right here you can get every single game made for it: http://www.esnips.com/web/romsatari2600?docsPage=1#files
have fun!
just for your enjoyment since i barely discovered this
M.U.G.E.N, 2D fighting game Mugen
