Utilities for manipulating desktop files.
http://www.freedesktop.org/wiki/Software/desktop-file-utils

desktop-file-validate: validates a desktop file and prints warnings/errors
                       about desktop entry specification violations.

desktop-file-install: installs a desktop file to the applications directory,
                      optionally munging it a bit in transit.

More information about desktop files can be found at:
http://freedesktop.org/wiki/Specifications/desktop-entry-spec