Recently, I stumbled up on an online tool called "Ip Browser" (IIRC, it was from domaintools.com) it serves the same purpose as http://ipbrowser.digitalmethods.net but the interface was quite different.
It showed the list of all the internet addresses starting from 0.0.0.0 to 255.255.255.255. On clicking any of them will give more information about that IP.
I cannot find it again now. I've been searching for past 2hrs. If any one of you know where it is, kindly point me to it.
EDIT: FOUND IT!
Actually, I was talking about http://domaintools.com/research/ip-explorer I don't know why on the earth they haven't linked to this page.