We are using OpenGC in Albatross UAV project.
You can find up-to-date version of the OpenGC at:
http://gitorious.org/albatross/albatross/trees/master/AlbatrossV2/groundstation/OpenGC

Next features were presented:
- configurable layout (via xml configuration file)
- navigation display
- two datasources for play: test datasource and FlightGear data source
- object-oriented approach

in case you are interested in the whole UAV project, visit Albatross:
http://gitorious.org/albatross/