The new OS X Lion has the Mac App Store built into the OS, as well as a redesigned Mail app, which includes support for Microsoft Exchange 2010. Apple says it has introduced 3,000 new developer APIs.
Phil Schiller, Apple's senior vice-president of worldwide product marketing, said: "Lion is packed with innovative features, such as new multi-touch gestures, system-wide support for full screen apps, and Mission Control for instantly accessing everything running on your Mac."
Adrian Bridgwater previously noted on Computer Weekly's developer network blog that the update would be delivered via the Mac App Store rather than by traditional CD-ROM. He also said the OS was a lot more "gesture driven" in homage to the popularity of the iPad.
Apple also previewed the next version of its mobile OS, iOS 5, which is available for Apple developers as a beta version and includes built-in Twitter integration.
"iOS 5 has some great new features, such as notification centre, iMessage and Newsstand, and we can't wait to see what our developers do with its 1,500 new APIs," said Apple CEO Steve Jobs at WWDC.
"Perhaps iOS 5's paramount feature is that it is built to seamlessly work with iCloud in the post-PC revolution that Apple is leading," added Jobs.
iCloud is Apple's new free cloud service to wirelessly store and update content, which can be accessed across its iPhone, iPad, iPod touch, Mac and PC. The company invested $500m in datacentres to support customer demand for its cloud service.
Mac OS X Lion provides "delta" app updates via the Mac App Store and will be available to download from the Mac App Store for £20.99 from July 2011. Mac OS X Lion is an upgrade to Mac OS X version 10.6 Snow Leopard.
Mac OS X Lion Server requires Lion and will be available in July from the Mac App Store for £34.99.