I have found numerous posts asking this same question but either I am not understanding them correctly or somethings broken because I cannot get multiple domains to work. Here's what I have (domains used as examples, not real).
The main wpmu installation is installed at http://main.com. I also want to run blog A and blog B from this installation on their own domains (http://blogA.com and http://blogB.com respectively).
I have set up wpmu to use subdomains and have created http://blogA.main.com and http://blogB.main.com and they work fine, both on the front end and back end. Now I try to map the domains and this is where I get tripped up.
I installed Wordpress Mu Domain Mapping pluggin, and activated it on the child blogs. Now I go into blog A and into the domain mapping and enter the correct server IP and http://blogA.com under the domain, however when I visit http://blogA.com there is nothing there but the public_html directory with no WP files at all. If I got to http://blogA.main.com it redirects me to http://blogA.com and I get the same empty directory.
I have a wildcard set up on all the domains and I have done the appache configuration. Why isn't this working?