The new iPad has been extremely popular since its launch at the end of last week, Friday, 16 March. First, Apple revealed that it sold three million units in the opening weekend, now Pocket-lint has learnt from one of our sources that the PC World and Currys group has so far sold 80 per cent more new iPads in the four days after launch than iPad 2s in the equivalent period last year.

In addition, after the midnight opening at the Tottenham Court Road PC World in London, a full eight hours before the Apple Store started selling the device, the shop sold a new iPad every 20 seconds for an hour-and-a-half - the time allotted before the shop closed its doors again.

Our source told us that the sales more than exceeded expectations.

In other, more official news, Currys and PC World has announced a new tablet and mobile phone trade-in service. Customers can visit to exchange unwanted handsets or tablet devices in return for gift vouchers to spend either online through the chain or in one of its national stores.

The new iPad isn't listed yet, but you can trade in your iPad 2 at the current value of £203.90 for the 16GB Wi-Fi version, up to £282.37 for the 64GB Wi-Fi + 3G model. Even broken devices are accepted (at lower rates, naturally).

Did you get a new iPad on launch weekend? Let us know in the comments below...