Is there a service that will identify where a site is hosted (presumably by IP)?
A good place to start is whois:
ARIN IP Address whois lookup: this allows you to see who "owns" (ie. who is the registered operator for) a given IP address block.
Internic whois lookup: this looks up the registered operator of a given domain name, along with their DNS servers (which may be operated by their hosting provider, but which could also easily be hosted elsewhere).
That will get you started. For more detailed information, use the traceroute command (or "tracert" on Windows) to see the path between your point on the network, and theirs.
Can't believe no one mentioned Netcraft
"What's that site running?" Top left hand corner.
This will also depend on whether the domain is owned and registered by the hosting provider or not. The best clue normally is the DNS records, however I used to roll my own DNS for a while using zone edit for example, and non of the domain queries would show who is hosting the domain.
However it should give you fairly accurate information as to who owns the domain.
You can use this website: http://www.quarkbase.com it will give you what you need plus many other info.
You can use our service Who is Hosting this Site?
Some points to keep in mind ...
If a website is hosted on a server farm (data center), then Who is Hosting this? will likely be showing the name of the data center and the web hosting company hosting this website.
When your site is using services like CloudFlare, it is difficult to find out the actual hosting provider. Accuracy level is 99%.
Benefits: Free utility, display who is the hosting provider, domain
ownership and who is records.