you will find the sozobon C compiler (V2 and V10 (?)). I haven't tested these files myself. But the archive (http://www.umich.edu/~archive/atari) seems to be a very large one. Maybe you can find even another compiler there.
I would like to download the Turbo C compiler from
http://groups.yahoo.com/group/atari-nederland/files/Borland2.zip and I'm registred on yahoo, but it still says that I'm no member of Atari-Nederlands and that's why I can't download it...
Can someone help me or put it somewhere else?