Cog is authored by Vincent Spader. It is released under the GPL. See COPYING for details.
The libraries folder contains various decoding and tagging libraries, which i have created Xcode projects for, and possibly modified to make compile on OS X. The various libraries are under each of their own licenses/copyrights.
All Cog code is copyrighted by me, and is licensed under the GPL. Cog contains bits of other code from third parties that are under their own licenses/copyright.
If you would like the photoshop sources for the various icons and graphics, please send me an email, and I will be happy to get them to you.
Share and enjoy.
--Vincent Spader (email@example.com)