You look up the DNS server: http://network-tools.com/default.asp?prog=dnsrec&host=di...

Then a whois record on the DNS: http://whois.domaintools.com/domaincontrol.com

Then a quick Google search shows results like "Note that anything ending in domaincontrol.com or secureserver.net is hosted by godaddy.com and/or wildwestdomains.com! If you have webmail, you can ..."