Thera are several versions of FD to EOS converters. Try a search on "Lens Mount Adapter" or "FD to EOS".
Here's a link to two on B&H's web site:
I don't know how well they perform. Most of the reviews on them have been less than glowing. Canon originally made an adapter that was for specific Canon lenses. It looks like the one to get, but I haven't been able to find one. Here's a link (thanks to NHL):
It doesn't look like the Canon adapter will work on your fisheye. But it might on other lenses... Post back and let me know how it works if you get one...