I Have literally looked over every possible solution from resetting the SMC to running scripts to enable/ disable the camera OR even adjusting the Quicktime plugins.
This is certianly an issue with the Macbook Air Mid 2013 models ONLY.
I am running 10.8.5 on my MacBook Air with Camera Model
Model ID: Apple Camera VendorID_0x106B ProductID_0x1570
Also, i did try and check this on my other 15"Mac Book Pro running 10.8.5 but it works perfectly well.
My Facetime HD Camera works with PhotoBooth, iChat, Facetime and NOT on Webex and Skype.
So much for getting the latest and the greatest.