I just wanted to share a product I have been using with anyone who may be in charge of managing email servers.
For the last 4 years or so I have been using a product called "XWall" to block SPAM on our system and it has been the best money we have ever spent. The price is currently $449 US which is a great price considering the amount of control the product offers. I have also never had to pay for an upgrade since the day we have had the software and they put them out pretty frequently to keep up with new SPAM techniques.
Here's a link to their web site if anyone is interested.
http://www.dataenter.co.at/doc/xwall.htm
Pete