I set up ClamXav to run with a cron job on my laptop. Since this is using cron, the output of the job is mailed to the my local account. I wanted see if there was a way that I could use the native mbox files in Apple's Mail. There were a couple of posts on Mac OS X hints that described doing this (hint 1, hint 2).
I discovered, as Joe Maller did, that Mac OS 10.4 doesn't use the mbox format to store its messages. It looks like it is using separate files for each message to allow Spotlight to index the messages.
The only way that I thought that it would be possible to read these messages in Apple's Mail was to setup a POP3 server on my laptop, that would read these mbox formatted files, and present a protocol that Mail can understand. I found this post that described setting up qpopper. I was actually able to skip from the unpacking step to the step that runs configure.
Qpopper claims to be the most widely-used server for the POP3 protocol. (I am not sure of that, I though that UofW software had been installed everywhere.) It is working perfectly for me, and I am now able to access all of my local mail.
I am not worried about running an additional server on my laptop. I have not opened this port in the firewall to allow incoming connections from other ip address other than localhost.