Quodlibet is an audio library tagger, manager, and player for GTK+. The majority of this package is written in python.
Quodlibet can be installed with
# emerge quodlibet
/usr/bin/quodlibet are the main binary programs, this package also comes with a command line utility
Most configuration is performed through the programs gui.
The man page has more details
$ man quodlibet
This section is in need of updates.