The speed of adoption has been far greater than the last model.
"It took 74 days to sell the first one million original iPhones," said Apple CEO Steve Jobs. He added that the iPhone is now available in 21countries.
The new iPhone uses 3G wireless technology and is faster than its predecessor, which used GPRS and was as a result slower when connecting to the internet. It also has extras including GPS mapping, Microsoft Exchange and the new Apps Store, which contains downloadable applications.
O2 is the exclusive service provider and outlet for the iPhone in the U.K.
In interviews carried out by Computer Weekly users praised the device's fast internet connection and the inclusion of GPS mapping on the device.
But users questioned the idea of only having one service provider and the requirement of having a monthly tariff.