Question : Bad Mail and returned mail SPAM

Hello
I'm receiving about 10000 bad mails per day. They all come from our domain being entered in the return address on spam mail. Other than deleting mail from \badmail folder on daily basis what can I do to stop this.
We are running Exchange 2000.

Answer : Bad Mail and returned mail SPAM

Microsoft have a tool for dealing with badmail.
http://www.microsoft.com/downloads/details.aspx?familyid=782aaf0f-6239-40ad-adda-97863d852ff7&displaylang=en

Simon.