Matt Cutts today announced the Google disavow links tool today.
This is good news for webmasters as this tool will now allow you to remove spam links. If you site has been spammed by thousand of spam link backs or if you’ve been a victim of negative SEO you can use this tool to tell Google not to take them into account while accessing your site. You can read the official announcement here.
The tool is very simple to you and is available in the Google Webmaster Tools account. All you need to do is download the links pointing to your site and then look for spammy links within the list. Once you’ve identified the spammy links, use the disavow tools page to disavow links.
Google will not take the disavow links in to account when accessing your site.