Hi,
Is it possible to find the hosting compnay that the site is using?
Or is it possible to check the ip range of hosting companies?

Number of ways:

Traceroute the domain - This can often give away where the server is located. As it displays hostnames of hops along the way.

Whois - Whois the person domain.

Netcraft - www.netcraft.com will display what the tag is of the IP in use via the site (should do anyway...)

Most probably a few other ways.

For example on netcraft:

http://uptime.netcraft.com/up/graph/?mode_u=off&mode_w=on&site=www.uh-shells.co.uk

UH Shells is the domain we use for our shell service. We colo with an ISP called Woaf Tech. It displays them as the Netblock Owner, as they are the owners of the IPs assigned from ripe.

Also shows who we used to be with. Dedipower (spit) :p

Also a nice idea to see what datacenter the host is in, many ips will be registered to the data centre in many cause's do a whois on the ips from

www.ripe.net - europe
www.arin.net - america
www.apnic.net - asia