We use a service provided by www.stopforumspam.com to check registrations and posts against a database of reported forum and blog spammers. If you believe that you are wrongly listed in this database, you can ask for your details to be removed by completing this form on their website.
This is what they say in their FAQ about being listed in the database:
Firstly, it's not an accusation of anything. A lot of the information that is listed is gathered from "honeypots" setup to trap spammers. Being listed on the site doesn't mean you have been sending spam. The IP address that you have, might have been inherited from someone that spammed, someone may have just used your email address or even that you have downloaded a virus or trojan. If you use the removal page and be polite, then we can figure out what has happened and get it fixed.