SubSites Web Part from echoTechnology
This is a very simple, but useful web part that shows all the sub webs for the current user. While limited to one level of sub webs, the download includes the code and can be modified to extend to all sub web children. The look and feel is based on the manage sub webs page from site settings in WSS 3.0. By modifying the code, a user can extend the web part to show all children sub webs recursively, or even change the look and feel.
Visit vendor website to download and to learn more.