I received a reply this morning from a posting on one of Security Focus‘ mailing lists from Tomasz Papszun, a guy working on Clam AntiVirus.
Clam AntiVirus is an anti-virus toolkit for UNIX. The main purpose of this software is the integration with mail servers (attachment scanning). The package provides a flexible and scalable multi-threaded daemon, a command line scanner, and a tool for automatic updating via Internet. The programs are based on a shared library distributed with the Clam AntiVirus package, which you can use with your own software. The virus database is based on the virus database from OpenAntiVirus, but contains additional signatures (including signatures for popular polymorphic viruses, too) and is KEPT UP TO DATE.
This is one of the best projects I’ve seen in a while, so check ‘em out by visiting their page, http://clamav.sourceforge.net.