I have started using the new version of Skype on Windows Phone 8.
It works, BUT , I can't seem to find how to use the Back Camera, only the front camera.
Is this by design ? or a Bug ?
Right now, this is "by design". Currently, Skype for Windows Phone 8 Preview does not support dual cameras. However, support will be added in a future update/release, but we have no fixed timescale for this at this time.
The 2.4 update is now out! Read about it here: http://community.skype.com/t5/Windows-Phone/Skype-
Thanks for your patience