Quote from Google Official Webmasters blog
"You asked, and we listened: We've extended our support for querying links to your site to much beyond the link: operator you might have used in the past. Now you can use webmaster tools to view a much larger sample of links to pages on your site that we found on the web. Unlike the link: operator, this data is much more comprehensive and can be classified, filtered, and downloaded. All you need to do is verify site ownership to see this information.
To make this data even more useful, we have divided the world of links into two types: external and internal."