Australian hosted spam filtering service with a 30 day trial. No hardware, no software required. Also offers POP3, web and Exchange hosting.

Proxy software for incoming mail.

Virus scanning and spam prevention based on blacklists and user feedback.

Online POP3 bayesian filtering service.

Managed anti-spam, virus and malware protection.

Spam and virus defense for businesses and service providers.

A hosted anti spam filtering service providing simple, anti spam, phishing and virus protection.

Document offers detailed discussion on how to filter junk mail in incoming SMTP transactions.

Dutch company offering managed hosted or dedicated virus and spam filtering, works through mx redirection. Free 30-day trial is offered.

Hosted service filters spam and viruses before they reach your network. This type of filtering can increase security, save bandwidth and reduce the load on your email server.