The Oxygen Icon Palette is licensed under the Creative Commons Attribution - NonCommercial - NoDerivs 2.5 License
Oxygen Icons are dual licensed under Creative Common Attribution-ShareAlike 3.0 and GNU Library General Public License, version 2 (or at your option) any later version. See: COPYING
To contribute, please familiarize yourself with Oxygen. You may also wish to join the mailing list shown below.
Work on Oxygen is being done using KDE's SVN server, and can be found on the web.
The Oxygen team is typically available on irc on FreeNode - connect to irc.kde.org, and join channel #kde-artists.
There are always new apps, oops, applications, that need an icon. Contact the Oxygen team to find out more.
A list of missing icons is being maintained here.
You can subscribe to the KDE artists mailing list by sending an e-mail to firstname.lastname@example.org with just "subscribe" in the header. Sometimes this list is virtually dead, then, nobody knows why, the list is full of life. Be amazed! If you want to take a look at the list before subscribing, you can look at the archives.
Here is the Bug list