Dan McDonald wrote A SpamAssassin-Enabled POP3 Proxy which runs swell on Win32. The only trouble I was having with it was that it didn’t run as a service, plus I hate trying to keep perl scripts running with wperl.exe. Well, I had to do something about that.
Being the code hacker that I am, I re-wrote it a bit to make it run compiled as a service using PerlSvc from ActiveState. The source code is REALLY ugly and needs some serious cleanup. But I have it running now to check my external mail accounts.
I actually installed the service on a server so now I just tell all my local machines to POP the mail from the centralized server and it all gets filtered by SA.