what we are using to almost completely stop spam is Secure Computing’s <a href=”http://www.ciphertrust.com/products/ironmail/”>CipherTrust Ironmail</a>. It is a great product. it sits between your email server and the network and filters all incoming emails. It uses 7 different algorithms to filter email based on your settings. Each algorithm will give a score to each email. The scores are added up and if it goes beyond a number limit that you have set it is automatically quarantined and you are notified so you can check it before it gets deleted.. This works great to filter out files too, (video, mp3′s, etc.). Nothing like a few video files to bog down your email server backups.