The Apple iPhone 4 allows its users to make video calls over Wi-Fi to any iPhone 4 owner. At the time of the launch of the iPhone 4, Apple dubbed this technology as FaceTime and called it revolutionary. The iPhone 4 was the first iPhone from Apple to feature video calling. Sadly, the ability to make video calls only over Wi-Fi was a huge disappointment for many. Currently, users can make a FaceTime video call only using the phone number of the other user.

However, in iOS 4.1 Beta 3 Apple has added an option to call users using their email id as well. The inclusion of this feature suggests that the next generation iPod Touch from Apple will feature a front-facing camera for video calling.

Hopefully, this also means that the next generation iPad will feature a camera for FaceTime as well.

(Source)