Apple used its developer conference in San Francisco to unveil a version of its Safari web browser for Windows PCs and to demonstrate a near complete version of its OS X Leopard operating system, due later this year. The company also disclosed details of how third-party apps can be supported on its iPhone, and new features in the server version of Leopard.

Mac OS X Leopard, due to ship in October, adds numerous features including a re-designed Finder to let users browse and locate files and applications. The major new feature is Time Machine, which maintains up-to-date copies of files to help users recover lost data.

The server version of OS X Leopard will include a wiki server, a Spotlight Server to quickly find content stored on other servers, and iCal Server, to co-ordinate scheduling across different calendar applications.

“Leopard is the best release of Mac OS X to date, surpassing even Tiger, and will further extend Mac OS X’s leadership as the most advanced and innovative operating system in the world,” said Apple chief executive Steve Jobs.

Meanwhile, Apple has made available a Windows version of Safari 3, its browser that will ship as part of Leopard. Apple claimed Safari is more responsive than rivals, loading web pages up to twice as fast as IE 7 and up to 1.6 times faster than Firefox. It features a private browsing tool to prevent information about a user's browsing history being stored, and runs on Windows XP or Vista.

Apple said that its iPhone handset, due for release later in June, will support Web 2.0 standards, enabling developers to build applications that look and behave just like native applications and which can seamlessly access the iPhone’s services.