First of all I would like to welcome old and new Captains to the Beta! Can't wait to shoot you all out of the sky, it is going to be a blast! (hue hue)
During the Pre-Alpha we had an unofficial Discord server set up so that people could talk about the game, ask for help, and team up. Discord is very similar to Teamspeak and Ventrilo, but has great support for text chat as well. Text is our main source of communication outside of the game. So even if you are not comfortable speaking English don't be afraid to join, we have people in all timezone and different countries on the server! Heck English is my third language.
If you plan to use it actively for voice chat while playing I highly recommend that you download the desktop client from here
See you in space Captains!