Simon put up a link at LinuxJournal to his site hostip.info that has done a really good job creating a hostip service (and some flashy, CIA-style graphics). He also mentions SarangWorld which I've checked out as well.
The API allows an easy way to bring this information into a number of other utilities:
Seems as though there are several people interested in compiling information on servers, ips and such. Now we just need to see about possibly coordinating our information.