Resolving ip, detective work

How can someone figure out what the DNS is for an ip? Such as, if I find an ip, 201.142.133.194 or something like that, how can I track down what the domain is? Such as investigating webstats and such, who's visiting what site and all?

Different tools - you can look it up at Arin whois , or you can do a nslookup

% nslookup
> set type=ptr
> 162.47.167.67
Server: ns001.intermedia.com
Address: 12.1.16.2

67.167.47.162.in-addr.arpa name = ns2.intermedia.com

You can also use dnswalk, dig, ... check out DNS.net for more tools.