ClamAV for Unix
Clam AntiVirus is a GPL antivirus toolkit for UNIX.
The main purpose of this software is the integration with mail servers. It provides a flexible and scalable multi-threaded daemon, a command line scanner and a virus database that is kept up to date.
ClamWin - ClamAV for Windows
ClamWin is a Free Antivirus for Microsoft Windows 98/Me/2000/XP/2003. It provides a graphical user interface to the Clam AntiVirus engine.
ClamWin Free Antivirus uses the GNU General Public License by the Free Software Foundation and is free (as in freedom) software.
Other Links
COSS v0.1 (clamav online specimen scanner)
Remote vulnerability in clamav, 4. Nov 2005
Debian Security Advisory, DSA-887-1 clamav -- several vulnerabilities