Please note that it is through the browser that WebMeeting can use your PC's camera. Therefore you can select a camera through the browsers settings. In Google Chrome which i use, when a WebMeeting is started there is a little camera icon on the address bar which can be clicked. Once clicked, you will be presented with permission settings regarding the camera and microphone . You can then click manage and on the next screen click camera. You can select a different camera from there.
A setting to natively control this from inside WebMeeting rather than having to do it from Chrome's settings is something we've wanted to add for a while now. We're hoping this will be something we will add eventually.