Multiple domains for one site with different logos

How can I make one site accessible with multiple domain names with different logos for each domain name? For example I have a site on domain A and want to make it accessible on domain B and C. When someone types domain B or domain C everything should be same as on domain A but the logo. These sites should use one database and one script!

The only thing that came in my mind is to create one big iframe for other domain with site A inside it and detect whether it's domain B or C using php referer...

Do you happen to know any better methods?

Thanks in advance

Make an index.php script, that will know what domain is currently accessed
$currentSite = $_SERVER["SERVER_NAME"] ;

and using that , assemble the site in a different way (for example, include different header, but the rest is the same)

$_SERVER[HTTP_HOST] also works.