Open Talk lets your Yahoo! Messenger contacts instantly connect a PC call to your PC without needing you to accept. Once connected, your friend will be able to hear all conversations and sounds near your PC. To set up one of your contacts with the new Open Talk feature, follow these instructions:
When Open Talk is turned on, friends on your contact list will see a purple telephone icon and a link with the words "Open Talk" to the right of your name. When they click the link, they'll automatically be connected to your PC for PC-to-PC calling fun.
To turn Open Talk off, just follow steps 1 and 2 and choose any one of the other status messages available.