Wordnet_tools is a python script which converts wordnet databases into dict databases. It is basically a rewrite of Rik Faith's "wnfilter" program, which unfortunately doesn't work for wordnet databases in the newer formats.
Wordnet_tools has been written entirely by Sebastian Hagen and is licensed under the GNU GPL.
The current version of wordnet_tools is available from svn.memespace.net, e.g. through http://svn.memespace.net/svn/hobby/trivialities/wordnet_tools/.
Wordnet_tool's parser has been written for the wordnet 3.0 database format, as documented in the wordnet manpages.
Unfortunately, to the best of my knowledge there was and is no such complete and exact documentation for the dict db format. Consequently, the dict-db output code is a result from combining information from the dictd(8) manpage with information gained from reading existing dictd databases, reading the dictd sources and empirical tests on how well dictd works with certain database files.
Wordnet_tools went through a number of iterations where it produced database files subtly incompatible with what dictd expected, but should now be reasonably correct and feature-complete.
This program has been originally written for the debian linux distribution and is used in the building of debian's dict-wn package.