Mod_rewrite help

[ntdesign]

I need someone to help me with a rewrite rule. I need:

http://example.com/domainname.com (or http://example.com/www.domainname.com)

to go to:

http://example.com/domain.php?url=domainname.com (or http://example.com/domain.php?url=www.domainname.com)

Thanks in advance :)