Help to configure audio in control panel?

I have vista my friend has xp when we use webcam to talk through messenger my voice keeps coming back at me another friend has same problem when talking to this same xp user on vista can go to control panel %26amp; click speaker icon how does she find this in control panel on xp to configure audio devicesHelp to configure audio in control panel?
I experience this also,, get a head set, or hold mic up to mouth..~

nars