I've written a very quick and dirty UI for GPG, using GTK+ and the Gtkmm toolkit. It's in no way feature-complete, but it is mostly usable. If anyone's interested, take a look at http://soli.inav.net/~rjhansen/fishtank.html ... Of course, patches, contributions and additions are welcome. (Particularly if someone who knows autoconf wants to contribute a configure script...)