One of the main disadvantages of iPad is lack of frontal camera. There were many talks on this subject and one of them has been turned into a concept, so far, unfortunately, not into reality. New conceptual accessory iSight for iPad will add camera to your iPad.
Generally speaking, this is easy to make such accessory, but there is problem with software. There is very likelihood that soon we will see such accessories, though they are supposed to work on jailbreak iPad only.
We also can hope that frontal camera will appear on the next version of iPhone and that special Skype version with support of video calls will appear as consequence. If this happens, I think we can wait for camera for iPad.