How do I know which links to remove when I get an “unnatural links” message?

Google Webmaster Tools says I have “unnatural links,” but gives little help as to which specific links are bad. Since I have never purchased links, I don’t know which ones to have removed, and I’m scared of removing good ones, which will hurt my traffic. Suggestions? dbizzle, Los Angeles Have a question? Ask it in our Webmaster Help Forum: groups.google.com Want your question to be answered on a video like this? Follow us on Twitter and look for an announcement when we take new questions: twitter.com More videos: www.youtube.com Webmaster Central Blog: googlewebmastercentral.blogspot.com Webmaster Central: www.google.com