There will be a small number of people who will have access to the gammas come January.
Users with Diplomat access or higher will be able to report feedback in the private Council forum.
The access classes are Citizen->Veteran->Diplomat->Ambassador.
How do we determine who gets access? Essentially it boils down to how effectively someone can report bugs and get us crash files so that we can figure out what went wrong and be available on #galciv on our IRC network to interact with directly.
So when you run into a crash in beta 5 of GalCiv II, look at the sticky posts at the top of the main GalCiv II forum and see how a proper report is. We'll be adding a few other people to the list before the second week of January when the first gamma is released.