If you want to use a different domain name with your web site, you can sign up for a new plan for the new domain name and forward it to your existing web site.
You can also register additional domain names and direct, or forward, them to your website. When visitors go to the new domain name in their browsers, they'll simply be redirected to your current web site.
(Hint: When you set up domain forwarding, select the "forwarding to a Yahoo! hosted site" option, and your visitors will never even see your original web address.)