http://www.testvirus.org/

25+ tests that use the EICAR test virus and other "tricks" to see if your malware protection is up to snuff. Just give 'em your email address, verify it by clicking a link sent to your mailbox, and test away. Pretty cool!

Just make sure it's not an email address you care about. Otherwise, you'll be emailing www.fixspam.org to clean up all your new mail!