how about it?
You can on this screen even change the address of the default zone.
For more information refer :http://technet.microsoft.com/en-us/library/cc263208%28v=office.12%29.aspx
Might be it is helpful for you.
how did you get this error? Could you please share the steps to reproduce?
usually, you only need to Add Internal URLs for AAM in situation such as configure reverse proxy;
for Publich URLs, system will automatically manage for you when you create/extend web applications or delete web application/Remove SharePoint from IIS web site.