ClamAV

From Grokdoc

ClamAV a GPL virus scanner featuring:

1) command-line scanner

2) fast, multi-threaded daemon

3) milter interface for sendmail

4) database updater with support for digital signatures

5) virus scanner C library

6) on-access scanning (Linux and FreeBSD)

7) detection of over 20000 viruses, worms and trojans

8) built-in support for RAR (2.0), Zip, Gzip, Bzip2

9) built-in support for Mbox, Maildir and raw mail files

[-- Will it/ can it automatically remove any virus it finds? --] -> Yes, -r flag.