Apple iPhone overhaul aims to keep its users app happy

Apple is to unveil a major overhaul of its iPhone on Thursday.

The iPhone 4 software is to pave the way for new versions of Apple's handset in the summer.

Experts say it could include the ability to run two programmes at once, and an overhaul of the iPhone's interface.

"A lot of people are crying out to be able to run more than one app at once," said Tom Dunmore of Stuff magazine. "However, Apple have to be very clever in the way they do it, so battery life isn't affected."

Apple will also announce details of this month's UK launch of the iPad, its 9.7in touchscreen computer. It was released in the US on Saturday and 300,000 iPads were reportedly sold in a day. Although it has received positive reviews, some users have complained of technical issues.