The only time that I have found that Google tells you where it found links to your site, is when the page on your site is 404 Not Found. In that case, Google has a 404 report in Webmaster Tools that includes information about what links to that URL.
If you have a valid page on your site, I've never seen Google tell you this information. The referrer field that Googlebot sends when it crawls is always blank. Google specifically makes the
link: directive incomplete and useless.
Bing on the other hand has a inbound links tool available in their webmaster tools. When you log in and validate your site, they will tell you about links they find to your pages.