The Wayback Machine - https://web.archive.org/web/20010509103021/http://homepage.mac.com:80/mactari/mactari/McStel.html

What's an emulator? It's what turns your state of the art G3 PowerPC Mac (or whatever you and I really have) into that 1978 marvel, the Atari 2600. To play games on it, you'll also need the cartridges. Many sites have "ROM images", which are copies of the software that the old cartridges held. And there are some games that people have written lately on the net that you can find at Nick Bensema's pages.

One important point to remember is that the emulator doesn't behave exactly like an Atari. There will be games you can't play because the programmers of the games started adding hardware inside the cartridges to supplement the Atari. MacStella doesn't allow for all of this stuff, but will play Combat, and Adventure, and hundreds of games you've never heard of!

When making a game, take this into account as well. Just because your code works on MacStella, don't assume the same code stuffed into a cart will work in an actual 2600! Playtest playtest playtest!

For more info on Stella 0.7, which is available on many platforms, check this page: "Stella 0.7"