Why is Google not showing all my backlinks? Where can I check for all the sites that linked to my page?
Unfortunately, Google choose not to display all the backlinks to a page. In addition, they only update the backlink index once every few months. Always use Yahoo or MSN to check backlinks.

You can use Mong's Backlink Watch to have an overview of all the backlinks to your page. You can also use my Yahoo Powered Backlink Checker to see the number of pages (internal, external, top ten) that linked to your page.