Apple unleashes iPhone 4 to the masses

Apple's much anticipated iPhone 4 has been released in the US, France, Germany, Japan and the UK .

At 9.3mm, the iPhone 4 is the thinnest version of the device yet. It features the highest resolution screen ever built into a phone, according to Apple, and the 3.5in Retina display contains 960 x 640 pixels. This is four times as many as the iPhone 3GS and 78 per cent of the pixels on an iPad.

Other features include a 5-megapixel camera with LED flash, HD video recording, an A4 processor and a three-axis gyro. Apple claimed that talk time is up to 40 per cent longer than previous models.

The iPhone 4 comes preloaded with iOS 4, the latest version of Apple's mobile operating system, which includes over 100 new features and 1,500 new APIs for developers.

IOS 4 was released as an upgrade earlier this week, and allows users to unify inbox messages, use wireless keyboards and enjoy 5x digital zoom on the cameras.

"iPhone 4 is the biggest leap since the original iPhone," said Apple chief executive Steve Jobs.

However, users who downloaded iOS4 took to Twitter to criticise the update, complaining about the time it took to upgrade software and how it had slowed iPhones down considerably.

iPhone 4 will be available by the end of July in Australia.