After a long Matt Cutts announced the new Google Webmaster Tools feature today during his PubCon keynote, and now available to all SEOs and webmasters to proceed with extreme caution.
ON more briefing Cutts said the goal with the launch is to keep the tool simple. To disavow links, simply all you have to do is upload a text file, with one URL per line (full domain or specific page), of links you want Google to ignore. These are the links that pointing to your site that you’re telling Google that you don’t trust.
Most sites should not use the Disvow Links with out using caution.
After uploading the file consisting of spam links Google will look at links you want disavowed as a “strong suggestion.” It can take several weeks to be disavowed, and more concerningly it is too much good if you wish to remove the bad links from the web, but this tool is for those backlinks you are unable to remove.
Proposingly Google launched it's Disvow Links tool to remove all paid links of bad quality pointed to your site and for which them you are untrsuty.
Google's Disavow Link's Works.
Look for example files.