When you drag a link from the browser address line in Internet Explore to the dock, it uses the page's name as the dock mouseover name. For example, I pulled the webmail.mac.com address over, but its name was 'login'. Not gonna fly. I found that if you save the site as a favorite first, you can edit the name and then pull it into the Dock from the bookmark window. It now has the customized name when moused over.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020508001536112