Suggestion for a Mac OS X Server Content Filter / Anti-Spam

[Scott Warren <sw () shelton org>]

Does anyone have a recommendation for a Mac OS X solution?  We have  
over 500 ldap users that use 4 different levels of being able to surf  
the web (wide open to no bad stuff to no bad stuff restricted even  
more to only what we define).  We are not against getting a network  
box to do the firewall/content/anti-spam stuff, just not sure which  
one to get.  I am curious about what Mac Server software products are  
out there. (yep, have been all thru google looking at some results)

Can anyone offer up some suggestions for a Mac environment?

Thanks!!

-- Scott