http://tools.dynamicdrive.com/favicon/

A favicon (portmanteau of “favourite” and “icon”) is the small icon that appears next to the address of a website in most browsers. Seemingly insignificant, a favicon is often a sign that a website designer has been thorough, and has taken every possible opportunity to put across their client’s message.

This simple tool takes any image and converts it into a favicon, which can easily be inserted into any webpage.