Start Fleet Operations. Go to the options screen, then 'voice over network'. there you can enable it and configure.
as soon as you join a game others will be able to hear what you are saying. (you have a small (v) behind your name). i am not sure yet, but that only may be working when you are hosting the game.

DOCa Cola

Thanks for the response.  I have enabled voice over network through the options section and a have the "v" behind my name in the multiplayer section.  My mic is working fine - tested it with other games.  Is there a key you need to hold down when speaking?

Thanks again.