Apple announces and dates iPhone 4

Apple has unveiled the long-awaited fourth-generation iPhone at its Worldwide Developers Conference in San Francisco, and said it will be out this month.

iPhone 4 is glass on the front and back with steel around the sides. "It's like a beautiful old Leica camera," was Steve Jobs' take. Check out our iPhone 4 photo gallery.

It's also the "thinnest smartphone on the planet" at just 9.3mm and has tons of new features including a much greater pixel density of 326 pixels per inch, superior battery life, a front-facing camera, a gyroscope and the iPad's A4 processor.

iPhone 4 will launch on 24th June in the UK, France, Germany, Japan and the US, with pre-orders kicking off on 15th June.

Pricing is only available for the US at the moment, where the 16GB version will cost $199 as part of a contract and the 32GB will go for $299. The iPhone 3GS will drop in price to $99 on contract.

The inclusion of the A4 processor means battery life is significantly improved. Apple reckons you should get seven hours of 3G talk, six hours 3G browsing, 10 hours Wi-Fi browsing, 10 hours video, 40 hours music and 300 hours of standby.

The gyroscope, meanwhile, promises "full pitch/roll/yaw sensing in 3D space". Jobs showed off a Jenga-inspired demo that used the gyro and remarked that it was "perfect for gaming".

Although not really gaming-related, Jobs also revealed that iPhone 4 will record HD video in up to 720p at 30 frames per second, and Mac program iMovie will make the jump to iPhone for $4.99 "if we approve it". (Funny guy!)

On that note, iPhone 4 has a new FaceTime video-calling feature that allows users to chat face to face via video over Wi-Fi. Both callers will need an iPhone 4, and it's Wi-Fi only for now. "We need to work a little bit with the carriers," said Jobs.

Apple also said that iPhone OS 4 - now renamed iOS 4 - will be available on 21st June for all existing iPhone and iPod Touch models, except first-gen iPhones, for free.

The operating system update will introduce multitasking, folders and other features.

There were only occasional allusions to the leaked iPhone 4 that wound up with Gizmodo during Jobs' address (and none about the police raid on the bloke who wrote about it), but the unusual advance press for the design did mean Jobs was able to address one widespread question - what are the lines for?

The stainless steel sides of the iPhone 4 are split in two places by a horizontal line. "This doesn't look like Apple... what are these lines?" Jobs joked.

"They are part of the primary structural elements of the phone... this is part of brilliant engineering. It uses the band as part of the antenna system!" There you go.

Earlier on in his speech, Jobs also said that iPad sales were still mental, with one born every minute. Sorry, one sold every three seconds.