[ale] Defending windows networks against email borne virii

[jb at devsea.com (John Wells)]

Any open or reasonably priced products out there that attempt to do this? 
We have an exchange server in house and a bunch of DAUs with anything from
XP to 95 on their machines.  We're currently being killed by a few worms.

I need to find something that'll cleanse these virii before they have the
opportunity to run it.

Looking for suggestions....

Thanks!
John