So far, however, FaceTime doesn't work over the cellular network and doesn't allow calls to Windows-based computers. It includes FaceTime, which enables users to make video calls to others who have the iPhone 4, the latest iPod Touch or a Mac computer. The iPhone 4, which was released in June, was the first iPhone to include a front-facing camera for video chat. In the first half of 2010, video calls made up 40 percent of all minutes spent using Skype's free calling services, the company said. Users pay to do things such as make calls from a PC to a landline or cell phone. Skype's software offers free services such as voice or video calls to other Skype users. The app allows the iPad and previous-generation iPod Touch to receive video calls, too, Skype said. Those with the latest iPod Touch will be able to make video calls over Wi-Fi. The app, which is being released Thursday through Apple Inc.'s iTunes Store, will let iPhone 4 and iPhone 3GS users make free video calls to other Skype users who are using the app or have access to the feature using Skype on their computer or other video phone. FaceTime software, which comes with iPhones, works only with Wi-Fi.

Users of the Internet calling and messaging service will be able to use both Wi-Fi and AT&T Inc.'s 3G cellular network.

Skype for iphone 4 video calls