Apple has unveiled Mac OS X Snow Leopard, an even more powerful and refined version of the world's most advanced operating system.

Snow Leopard builds on a decade of OS X innovation and success with hundreds of refinements, new core technologies, out of the box support for Microsoft Exchange and new accessibility features.

Snow Leopard will ship as an upgrade for Mac OS X Leopard users in September 2009 for $29. ''We've built on the success of Leopard and created an even better experience for our users from installation to shutdown,'' said Bertrand Serlet, Apple's senior vice president of Software Engineering.

''Apple engineers have made hundreds of improvements so with Snow Leopard your system is going to feel faster, more responsive and even more reliable than before.''

Users will notice a more responsive Finder; Mail that loads messages 85 per cent faster and conducts searches up to 90 per cent faster; Time Machine with up to 50 per cent faster initial backup; a Dock with Exposé integration; a 64-bit version of Safari® 4 that boosts the performance of the Nitro JavaScript engine by up to 50 per cent and is resistant to crashes caused by plug-ins.

Snow Leopard will  includes an all new QuickTime X, with a redesigned player that allows users to easily view, record, trim and share video to YouTube, MobileMe or iTunes. Snow Leopard.

Half the size of the previous version that frees up to 6GB of drive space once installed, the Snow Leopard Server also comes with Podcast Producer 2, a new version of the tool which allows you to, well, create and publish podcasts; one of its new features is Podcast Composer, which allows you to automate the completion and publishing of podcasts.

The iCal Server has also been bumped to version 2, which includes, among other things, real-time calendar access from iPhones, and a new web based calendar client.

Moreover, the Wiki Server 2, Address Book Server (which makes sharing contacts easier), and Mobile Access Server, which enables you to access firewall-protected services with your mobile Mac or iPhone, are asdo incorporated in the Snow Leopard.