Examples of good Favicon Design
favicon (short for “favorites icon”), also known as a page icon, is an icon associated with a particular website or webpage. A web designer can create such an icon, and many recent web browsers can then make use of them. Browsers that support favicons may display them in the browser’s URL bar, next to the site’s name in lists of bookmarks, and next to the page’s title in a tabbed document interface.
Smashing magazine has a list of some well designed favicons and links to favicon generators and tutorials