Apple introduced a number of improvements to its mobile and desktop operating systems as well as its MacBook Pro and Air computers Monday at the company's annual Worldwide Developer's Conference in San Francisco. The conference is primarily aimed at programmers who will develop software and apps that run on Apple's products but also provides a glimpse of what's in store for some of its most popular electronics in the near future.

Among the highlights was a preview of iOS 6, which will debut this fall as a free software update for the iPhone, iPad and iPod touch mobile devices. The new iOS includes support for FaceTime video calls over cellular networks (not just WiFi) as well as the ability to post to Facebook directly from Notification Center, Siri and Facebook-enabled apps like Photos, Safari and Maps. This tight integration with Facebook comes amid the latest round of rumors that Facebook plans to develop its own smart phone.

Apple also announced that its Siri voice-activated personal assistant software is now available for the new iPad (not just the iPhone 4S) and has broadened her repertoire to include several new languages, including Spanish, Italian, Korean, Mandarin and Cantonese. Siri users can also ask the software to update their status on Facebook, post to Twitter or launch apps.

The company's Mac OS X (Lion) operating system is also on the move as the new Mountain Lion debuts next month via the Mac App Store. Among Mountain Lion's most notable features is a reliance on the company's iCloud service, which lets Mac, iPhone, iPad and Air users store files and information on Apple's servers so they can be retrieved using any of these devices.

Originally introduced for the latest version of the iPad, Apple's high-resolution Retina display will soon be available on a 38-centimeter MacBook Pro. The company claims its Retina display has more than five million pixels, or three million more than a high-definition television. At the company's 2010 Worldwide Developer's Conference, Apple co-founder Steve Jobs claimed that the Retina display's pixel density is so high the human eye could not distinguish individual pixels from a normal viewing distance—about 12 inches from the eye—although this claim has since been disputed. The new MacBook Pro, weighing in at about two kilograms, is currently available starting at $2,200.

Meanwhile, Apple today updated the MacBook Air with processors, graphics and flash storage twice as fast as the previous version of the laptop. The entry-level 28-centimeter MacBook Air starts at $1,000.

Image courtesy of Apple Inc.