To add a favicon to your SiteBuilder site, first you need to create the favicon image. This can be done manually on your computer or you can use an online favicon generator. Here are several such generators:

Dynamic Drive Generator

Graphics Guru Generator

1Favicon Generator

Once you create the favicon, you should upload the favicon.ico file to your public_html folder.

Clear up your browser's cache and reload your website. The new favicon will appear in your browser's address bar :)