I've been writing text editors for many years and since I wanted to change the layout of a recently downloaded .epub I decided it would be best to add support for this format into my editor directly.
Japi is an open-source Gtk2 application and should be able to run on any OS that has GNOME installed. I've created two binaries for Ubuntu 8.10:
http://www.xs4all.nl/~hekkel2/japi-a....9.7-b1.tar.gz
http://www.xs4all.nl/~hekkel2/japi-i386-0.9.7-b1.tar.gz
To use this software, download the appropriate file and unpack it. There's only one file inside the archive and it does not need to be installed to be used. However, you can install it system wide by running the command (from a terminal):
sudo ./japi -i /usr/local/bin/japi
As you can see from the version number, Japi is still considered to be beta quality. But I thought some of you might find this interesting. And of course, I'm very interested in feedback.
-maarten