Can someone only point a sub domain to a sub site blog in WPMU?

For instance, I have a WPMU blog network that is open to everybody to create their blog site.

How can a sub site/blog admin user point a sub domain to this sub blog site?

For example, this user's official website is http://www.users-domain.com, and he wants to point a sub domain: blog.users-domain.com to his blog site hosted on my WPMU network.

How to achieve this? I guess you may have some plugin to do that, too.

What needs to be set in Godaddy (domain register) and what needs in WPMU and Cpanel (hosting), respectively?

Thanks :slight_smile: