To use the Voice features in Second Life, you'll need to set up your microphone or headset.  SBMI recommends headsets with builtin microphones.

Just follow these simple steps to set up your audio devices for voice chatting.

• Connect your microphone or headset via audio-in or USB before you launch Second Life.

• If you're on a Windows machine wait and make sure Windows has finished installing the device drivers. You will be to notified by the system tray on the lower right side of your screen. 

1. Launch Second Life Client
2. Open the Preferences window by choosing Me > Preferences or pressing Ctrl+P
3. Click the Sound & Media tab
4. Click the Input/Output devices button, then change the input and output devices to your preferred microphone and speakers
5. If your mic is working, you will see green bars in the input level monitor
6. Click OK
7. Click the button to the right of the chat input field to toggle your microphone on and off