<p><a href="http://msdn.microsoft.com/library/books/win95ui/chpt13-07.htm">Context Menu Handler Interfaces</a></p>
<p><a href="http://msdn.microsoft.com/library/periodic/period99/cutting1199.htm">Customizing Microsoft Internet Explorer 5.0</a></p>
<p><a href="http://support.microsoft.com/support/kb/articles/q177/2/41.asp">HOWTO: Adding to the Standard Context Menus of the WebBrowser Control</a></p>