The LOC record, described in RFC 1876, has a bit of a chicken and egg problem (no applications will use it until it's widespread, and it won't become widespread without an application to motivate people) compounded by the fact that it's just not easy enough to get the information people need to put host locations into the DNS.
It is quite easy to put the information into the DNS zone file(s) once you have it; a simple example giving the latitude, longitude, and altitude of a particular router in Cambridge, MA (as opposed to Cambridge, UK):
cambridge-gw LOC 42 21 43.528 N 71 5 6.284 W 5m
These pages exist to help get LOC over the hump, both by making it easier to put the information out there, and also as a resource to help people develop or find applications that use LOC records.
Some may ask "why use LOC records instead of a centralized host name/IP to lat/long database?" There's room for both, certainly, but I think LOC records have the important advantage of being decentralized. This means that they can be installed and updated by individual DNS admins as machines are added, moved, or removed; it also means that they don't have to depend on heuristics like "use the InterNIC registered address for all hosts in this domain", which fails miserably on geographically diverse domains such as hp.com or ml.org. (Unfortunately, they have the important disadvantage of being decentralized; this means that using them for general purposes requires a fallback plan that uses a centralized database, because not all sites will have put them in at any given time.)
If you have an application that can make use of location information for hosts, I encourage you to encourage your users to put LOC records in the DNS, possibly by linking to these pages; that's what these pages are for. (Also, let me know about it so I can add it to the list of LOC-aware applications.) If you're interested in writing one, let me know; I may be able to offer suggestions or assistance.
Given the near-infinite willingness of people to put free advertisements on their web pages as long as there's a spiffy little icon available, I've made an "RFC 1876 Now!" GIF that people are welcome to use and copy.
Please use it to link to this page (http://www.kei.com/homepages/ckd/dns-loc/), as sub-pages may move around or disappear.
Sample HTML code is given below. (I'm willing to let people inline from this server as long as the load doesn't get too high, because I would like to encourage caching; if and when the load does get too high, I may ask folks who get lots of hits to serve copies of the icon from their own servers.)
I've also just (1997-07-01) set up a mailing list for discussion of all aspects of RFC 1876 LOC resource records.
Topics will range from evangelism techniques (convincing your ISP to put in at least vague records for their backbone routers) to ideas for applications to announcements of applications/libraries/tools to "we just put in LOC records for the following zones, please give them a try".
I'll also be posting periodic lists of known LOC records for use in testing applications and so forth.
I don't know what the eventual traffic load will be like; I'm hoping for steady but not unbearable traffic at a fairly high on-topic level.
(By way of assisting that, the list will require users to be either subscribers or on a separate "accept" list to send messages to the list.)
The list is managed by SmartList, which unlike some other mailing list managers uses the traditional "-request" address. To subscribe, send mail to email@example.com with a subject of "subscribe" (without the quotes).