Good, reliable spam filter for Outlook 2k3

[TriedandTested]

Please suggest something either free or that doesn't cost too much.

Having problems with a few staff members' email addresses of late so would like to test a few things to see what can be done.

I've looked at spampal but from what it says you have to setup your email to come through one of their proxies..not keen on that.

 

[JayMax]

I'm presuming this is not on Exchange?

I use spambayes - a free add in for Outlook 2003 and have been rather impressed with it.
It has taken about 1 or 2 weeks to learn my email patterns and with only one tweak of lowering the 'junk suspects' scoring my inbox is spamfree and hassle free.
It's the best free solution I've come across yet