I'm not sure what you mean with "identify the host of a particular website", but here are some possible answers to your question:

(gwhois is really nice, and it's in Perl :)

I want to know what kind of server the host is running on

$ HEAD http://host/ | grep "Server"

I want to know who registered a domain name

$ gwhois domain.tld

I want to know who owns the netblock of the IP in question

$ gwhois www.xxx.yyy.zzz

I want to lookup a country by IP address

See Geo::IP