It would be nice if some of you veterans on this forum actually posted comments that addressed an issue rather than flaming the newbies. Just a thought...
As for the issue at hand, there is something that can be done about it, depending on how much control over your e-mail domain you have:
There is something called an SPF(Sender Policy Framework) record that mail servers use to authenticate the server that sent a message against a record that states which servers on the internet should be allowed to send mail for a given domain. You can find out more here:
http://www.openspf.org/Introduction
If your e-mail is hosted at a web-host like Register.com, GoDaddy.com or DomainsLikeMagic.com, you can login to your domain record manager and add the record. In addition, if you have a mail server, you can have it set to allow only certain types of incoming mail, keep it from being anonymously relayed from to send spam, etc. Unfortunately, some servers on the net still do not use these SPF records to validate senders or any other authentication, which renders them useless. Thankfully, larege ISPs and domains like aol.com will bounce mail sent from an unauthorized address or server.