Archives

Shareware.com: Shareware.com is a virtual software library containing about 250,000 programs available free on the Internet, including catalogues of software for DOS (Simtel, Garbo), Windows (Cica), OS/2 (Hobbes), Macintosh, Unix, Linux, Amiga, Novell, you name it... Great search engine on a fast, well-designed site.
OS/2: Yahoo's OS/2 archive.
Unix: Yahoo's Unix archive.