Yeah cc and os gpl don't really mix that well, but... oh well.
If you really want to license it, you might try to make a plugin out of it.
Actually I'm not even sure you can license it at its current stage.
Its a cool concept, one thing I notice is some of the panning seems to be a little exaggerated from the side, one balloon will zoom in real quick while another will stay the same size.
Any way good luck with it.