With a microphone attached (or built-in) to your computer, you can record and deliver your outgoing message from the web.
Click on the group name in the left hand margin that you want to record the message for and follow these steps.
1) Call Balance
Your Call Balance must be equal to or greater than the number of members to whom the message will be sent.
2) Record and Save Your Outgoing Message
Record up to a 60-second message.
3) Deliver Outgoing Message
Once you save your recording, you can initiate delivery to your group phone list.