Apple has announced that its CEO Steve Jobs will showcase new versions of its desktop and mobile operating systems, plus a new service called iCloud, at its WWDC conference in Calfornia on Monday June 6.

Alongside the expected demo of the much publicised Mac OS X 10.7 'Lion', the company has announced in a press release that it wiil be showing iOS 5 -- an upgrade of the software for the iPad and iPhone. It will also show iCloud, described as "Apple’s upcoming cloud services offering."

No details about iOS 5 and iCloud have been revealed. That Apple has announced the names in advance of the keynote speech at WWDC is unusual enough.