The Prefix WhoIs Project provides a whois-compatible client and server
framework for disclosing various up-to-date routing information.
Instead of using registrar-originated network information (which is often
unspecific or inaccurate), Prefix WhoIs uses the Internet's global routing
table as gleaned from a number of routing peers around the world. Other
sources of information, such as imported data from ARIN are also supported
(a separate agreement with ARIN is required).

WWW: http://pwhois.org/