IP-address.com

Look up any ip here and also find its location very handy
site for fast look ups so go try it out on your self or on
some ones ip your wanting to know about, its a free
service.

IP Tools Network

Iptools.com is one of the best online ip scanning site with

lots of nice online search tools and more recommended
for quick and fast ip look up's.

Central Ops.Net

This site is a collection of Internet utilities developed by Hexillion using its HexGadgets components. Most of the utilities have ASP or ASP.NET source code available.
Very useful tools that any one can use when you want to look up information on some one! Go there now check it out....