The first thing to do is set up a Feedback Loop with AOL for your server Mark. That can be done
here. This will cause them to send you mail that ends up being reported as a Spam/TOS violation to them when it comes through your server's IP number.
Note that you won't see some information because they strip out some mail headers. But you may get some hints from this.
If it's a situation where someone has a mail redirect set up for a domain being hosted on your server, it will help spot that because you can see the original delivery address to your server. If they report the mail as spam (as most do) to AOL that is. The same goes if someone is running a mailman mailing list, though the TOS/Spam report won't show you the final delivery address.
If it's a rogue script, tracking it down is going to be more difficult. But can be tracked down.
When you see something funny like this in your maillog try to trace it back by the Delivery number (77547 in your example) and the msg number. If there's still that msg number in your queue do a
locate 8445364, which will give you the location of a few files in the /var/qmail queues. You may be able to pick up some additional clues by viewing those with nano/pico/vi.
If you see you UID 48, then you know it was some type of script sending it since that's apache.
Between the AOL Feedback Loop and a little bit of detective work, paying close attention to the email headers, you should be able to track it all back to the original sender.