Spam email and address spoofing problem

Recently my domain name has been used by spammers to create fake email addresses in the From field for spam e-mail. I first became aware of this when I started receiving “Return Mail Notifications” in my inbox. My server is not being used to send the e-mail and the usernames do not really exist. The targets are all AOL users and the headers indicate that the e-mails originate from many different domains. I have contacted the hosts for some of the domains involved but this has been very time consuming and not effective. Is there any way to combat this problem or is my domain name trashed?