Hexamail Guard
Hexamail server based anti spam integrates with all versions of exchange server and all smtp email servers. most comprehensive spam filter features provide the most effective anti spam. hexamail also provides disclaimer, mail alerting, automatic routing, pop3 downloading and auto reply/responder features
http://www.hexamail.com/hexamailguard/?referrer=g-hgc1
GFI MailEssentials
Gfi mailessentials is an anti spam filter for microsoft exchange server, which includes anti-phishing and exchange disclaimer features.
http://www.gfi.com/mes/
IHateSpam for Exchange
Award winning anti-spyware, anti-malware and email security software for home, smb and enterprise. protect your personal information and remove spyware, malware, filter spam, block viruses, and defend your pc or your network.
http://www.sunbelt-software.com/product.cfm?id=931
MailFender
Maildisclaimer lets you add disclaimers in exchange server based on a set of rules and templates that you control.
http://www.mailfender.com/
Pinjo Revealer
Pinjo revealer, spamfilter technology
http://www.pinjo.nl/
XWall Spam Filter
Xwall the advanced spam mail filter for microsoft exchange servers and other smtp based e-mail servers. the xwall email control system goes far bejond a spam filter.
http://www.emailprofessor.com/xwall.htm