This is my latest hobby on the internet, I came across this site by accident....................
You'll need the the MAME software first (this the program that you download the individual games into).......
Go to http://www.fileplanet.com/dl.aspx?/classicgaming/mame32qa/mame32v67b.exe this is the windows based version. You will have to download from the non members link.
Once you have the above program you need the games...................I like the following sites...........
http://www.clubi.ie/ogiee/Ankman/ (no membership required to download)
http://www.mame.dk/ (Free membership, to download) .....Once you choose a game in the details page scroll down to the bottom, you need 0.67 ROM. Click to download, it will ask you if you own the game or not just click on that you own it, the download will begin. Some only take a few seconds, depending on your connection speed. http://gamingmeca.0catch.com/atari.html You must only use ROMs for the MAME software as these are a replica of the origional circuit boards from the machines in software form. Do a search on the internet for ROMs and you will find hundreds of sites.
When you have the individual game on you PC, leave it in zip format and copy it to the ROM file in the MAME program. Refresh the MAME menu by clicking on file at the top and Audit all game. The game should then apear in the list. Click on it to play. Don't forget your PC is now like the Arcade game so you need to add credits, do this by pressing the 5 key. Then press 1 or 2 keys for one player or two. The Ctrl, Alt and arrow keys are generaly the movement keys.
ENJOY!
Qwerty