I don't know if you specifically mentioned it in your 'spam' column, but "Spambytes" site states that it can not be used with "Outlook Express". Do you know differently?

Can really use something like that for the items that slip through Postini.

First, the program we're talking about is called SpamBayes, so called because it uses a Bayesian algorithm for predicting spam in messages. SpamBayes is an excellent open-source program and is my final line of defense from the 7,000+ messages I get each day. And yes, that's after Postini does some amount of pre-processing.

Before we go onto the answer, let's also discuss Postini. Postini is a mail processing service. In my case, I get it from the uber-excellent ISP Prominic.NET, but you can contract your Postini service through Postini as well. If you run your own mail server, you can set up your mail MX records so that all your company's incoming mail first goes through Postini and then is sent on to your mail server, with the obvious spam filtered out.

Postini doesn't get everything (about 1/3 of all my incoming mail is caught by Postini), but it does help. And we can use all the help we can get.

SpamBayes installs directly into Outlook 2003. As yet, we don't have any firm word on how well it works in Outlook 2007, so we don't recommend using it with Outlook 2007 -- yet.

Mitch is right. SpamBayes doesn't work directly within Outlook Express, the free email client that comes with Windows XP. But, the SpamBayes site says this: "It does not work with Outlook Express -- see below for other options."

This is where good reading of the page comes in handy. It doesn't work with Outlook Express, but there are other options. And they're below. In fact, the phrase "other options" has a link, and when you click it, you're taken to a paragraph that states:

Windows users using other mail clients and retrieving mail via POP3 can download the same installation program and use it to install a binary version of sb_server, including a tray application.

Hmmm... so if you're using a mail client besides Outlook 2003, you can use this sb_server thing. So, what's sb_server? Here's the description:

sb_server provides a POP3 proxy which sits between your mail client and your real POP3 server and marks mail as ham or spam as it passes through. See the README for more. sb_server can also be used with the sb_upload.py script as a procmail (or similar) solution.