[dba-Tech] Spam, spam, spam, spam ....

Hi all
A mate has asked my advice, so I'm bringing the question to
they-who-know-everything (ie you lot). Can anyone suggest good, free,
spam-blocking software, compatible with Outlook Express, that uses
techniques more sophisticated than putting rules in Outlook looking for
specific words. An example he gave me is an email received recently with no
Subject and just an image in the Body, oh and one of those sent-by's which
changes all the time. Is there anything out there which could detect that as
spam? At work our ISP uses heuristics to spot heavy traffic coming from a
certain source and flags it up tht way, but I'd guess that that's always a
paid-for service. What do you all think?

-- Andy Lacey
http://www.minstersystems.co.uk