Discovered today: http://triviaware.com/macprocess/all. Very nice if you have a question about one of those mysterious processes that run on your Mac. Such as: Why is "AirPort Base Station Agent.app" running on my desktop machine, even though that machine is not equipped with Wi-Fi/AirPort and, in fact, there is no AirPort base station in the entire household?
Anyway, you can also upload a text file created with
ps -A and let the website "explain" the processes to you. Upload here.