Given recent discussions on the limitations of the DNS, I recommend the
following well written paper by John Klensin from the Internet Engineering
Task Force.

"Role of Domain Name System"
http://search.ietf.org/internet-drafts/draft-klensin-dns-role-01.txt

"The original function and purpose of the DNS is reviewed, and
contrasted with some of the functions into which it is being forced
today and some of the newer demands being placed upon it or suggested
for it.  A framework for an alternative to placing these additional
stresses on the DNS is then outlined.  This document and that
framework are not a proposed solution, only a strong suggestion that
the time has come to begin thinking more broadly about the problems
we are encountering and possible approaches to solving them."

A further paper from John Klensin - although more detailed and technical:
"A Search-based access model for the DNS"
http://search.ietf.org/internet-drafts/draft-klensin-dns-search-02.txt

"This memo discusses strategies for supporting 'DNS searching' finding of
names in the DNS, or references that will ultimately point
to DNS names, by a mechanism layered above the DNS itself that
permits fuzzy matching, selection that uses attributes or facets, and
use of descriptive terms."

Bruce Tonkin