Apple chief Steve Jobs yesterday announced that the iPhone would be opened up for developers to build third party applications. A software developer's kit will be released in February, he wrote, adding that the kit would also work for building applications on the iPod Touch.

While the move is not altogether unexpected, it is a little surprising in the wake of Apple's warnings to hackers not to install unauthorised software. Especially when the warnings turned out to be true and many curious tinkerers found their iPhone rendered useless.

Jobs explained the late date of the kit's release: "It will take until February to release an SDK because we're trying to do two diametrically opposed things at once — provide an advanced and open platform to developers while at the same time protect iPhone users from viruses, malware, privacy attacks, etc. This is no easy task. Some claim that viruses and malware are not a problem on mobile phones — this is simply not true."

Jobs said that the company was working on a system that will give developers broad access to natively program the iPhone's software platform.

Jobs noted that other manufacturers were making moves in allowing developers to build applications, making note of Nokia's approach and its use of a digital signature to track applications to their developers so as to minimise security threats.