I would like to hear about uses of DNS LOC records not listed here; please send mail to me or to the DNS LOC users' mailing list if you know of (or are working on) any.
CAIDA (Cooperative Association for Internet Data Analysis) is working on a series of Internet visualization projects (including visualization of MBONE and caching hierarchy connectivity) and related tools (including Mapnet).
A number of "visual traceroute" applications use DNS LOC for geographic display of packet routes. On Windows, there are VisualRoute and GeoBoy; on the Macintosh, there is WhatRoute. UNIX systems can use CAIDA's Java-based GTrace.
My LOC to Maps web demo is also available; it's written in Perl using CGI.pm and Net::DNS.