How Do You Chat On Yahoo Using Webcam?

Sign in to Yahoo Messenger, Go to either Chat room and then select a user or you can simply select a person added in your Messenger and double click it. Once you clicked on that person's display name, A chat window will appear in front of you for chatting with that person.
Now, click on "Actions" button on the top of chat window. A menu will appear down. Select "Invite to view my webcam" from the menu (It is usually the third last option). After that, the person on other end can see you with no charges (except for using Internet).