Apple has introduced the iPhone Software Development kit with which developers can begin building third party applications for the device.

Apple's Scott Forstall first discussed existing web applications for the device, listing those from Facebook and the Bank of America and mentioning that the latter application already accounts for 25 per cent of the mobile banking transacted by the giant US bank.

Then Forstall let it drop: "Starting today, we're opening up the same APIs and tools that we use internally," he said, scotching rumours the SDK would be delayed until later this year.

To create the development framework, Apple engineers created a new framework for application development, based on OS X's Cocoa environment, which it calls Cocoa Touch.

The core OS is very like Mac OS X, but with memory optimisation and power management features - and the provision of built-in support for touch-based controls, rather than OS X's mouse and keyboard paradigm.

iPhone SDK supports Core Audio and a whole new range of services, including Core Location - basically the location system based on mobile phone masts and WiFi Base Stations that lets iPhone users find out where they are.

But what's really important for developers is that the API will allow them access to the address book, certain databases, and location information to create location-aware apps. along with video and audio capabilities, 3D effects, and an embedded version of OpenGL.

And exciting news for gamers - the iPhone SDK also lets developers make use of the three dimensions of the device's motion sensors.

"We think we're years ahead of any other platform for a mobile device," he said.

Apple has chosen to deploy the development kit through its existing Xcode environment. There's an interface builder, iPhone simulator and various tools to check memory usage and so on in order to ensure better performance.

Once a developer has created an application, the app can be sent straight across to an iPhone for testing.