- A new Voice Bar will appear that provides options and indicates who is currently speaking and when you're talking. It can be docked with any chat windows.
- A new Voice Users window will show all users in the current channel. This window can be changed to be transparent and show only active speakers if you'd like.
- Group and Raid windows have speaking indicators to show who is currently speaking.
- Voice options are available in the Options Menu under the "Voice Chat" tab.
- If you're not currently in a voice channel, you will be placed in the first channel that becomes available. Subsequent channels that become available can be selected through a dropdown on the Voice Users window, a button on the Voice Bar, or a link that appears in text chat.
- Left Control is the default push-to-talk key. You can change the key in the "Voice Chat" tab of the Options Menu.
- If you need more info, do "/help vchat" in game.
Also, you can see a mini-feature on the EQII forums.
More info at Voice Chat