My name is XXXXX XXXXX I'd like to help you with your problem. First I'll need some more information. Please let me know the version of Mac OS that you are using, the version of Skype that you are using, and also whether it is the built in i-Sight camera or an external camera. Plus have you tried using the camera on iChat? One more thing, can you please further clarify the type of trouble you are having with the webcam?
When you get back to me with this information we'll further be able to explore your problem.