This week's book giveaway is in the Testing forum. We're giving away four copies of The Way of the Web Tester: A Beginner's Guide to Automating Tests and have Jonathan Rasmusson on-line! See this thread for details.
You're asking how to find mail servers, or, once you're connected to a mail server, how to find its address? Note that without the address, you can't connect to the mail server, so I'm really not sure what you're asking. Can you rephrase the question?