App of the Week - Skype

Price: £free

Platform: iPhone 4

Forget the digital TV switchover. The biggest technological shift is the move from mobile minutes to mobile data - and it's almost complete. The latest version (3.0) of the Skype app now offers free video calls over 3G as well as Wi-Fi for the first time, letting you watch while you chat on your iPhone 4.

Of course, for the best part of a decade, video calling has been an application in search of an audience. 3 has long given up trying to persuade users that they want to hold their phone at arm's length while shouting. But the tide may be turning.

FaceTime gave video calling an injection of Apple cool, and now Skype widens your pool of potential video chatterers. The new Skype app works pretty much as it did before. You log in to your Skype account and you can see the status of all your contacts. On each page, you now have the option to place a video call, as well as the usual voice, SMS and chat options.

Fire up a video call and you can choose between the iPhone's front camera (so they can see you) or main camera (for show-off shots of your surroundings). The other party's webcam is cropped rather than squeezed, so they may have to wriggle around to let you see them.

Video call quality is pretty good. Our test call on a moving train held a 3G call impressively well. Video was a little smeary but smooth and stutter-free. Audio faded in and out a little but was in synch and crisp enough when it was working.

Overall, video quality is definitely sub-par compared to FaceTime - but then FaceTime is currently limited to Wi-Fi only. As you might expect, video calls gobble power - a five-minute call seemed to cost around 5 per cent of my battery life - and you may want to keep tabs on your data use, too.

Add in Skype Out for cheap calls to real-world numbers and a Skype In number for incoming calls, and it's easy to imagine side-stepping your mobile company's phoneline altogether. Now to find a provider that just wants to sell you data without that pesky phone number attached.