Link Popularity Tool
This is an all in one tool to check the number of pages that link to you in AlltheWeb, AltaVista, Google, HotBot, MSN Search, and Yahoo!, as well as check for your site's presence in DMOZ and Zeal.
A site that has a Link Popularity Score of 1,000-5,000 is considered average. A site with a Link Popularity Score of 20,000 is considered popular. Sites with a Link Popularity Score above 100,000 are Internet "Icons".