Check out the underlying web host of a website with Who is Hosting This here.
To use the service, simply type in any domain name, and you’ll get a link to the company that’s hosting this particular domain. However, not all results are accurate, although it’s pretty close, as the script is using the IP address of the website to determine the web hosting provider from WHOIS database. If the owner of the IP address is not the web hosting company itself, or the web host leases the IP address, then the results will be invalid.