By Kasper Jade

Published: 04:20 PM EST

Software engineers at Apple Computer have been toiling away on a new set of features that will allow users of its next-generation Mac OS X operating system to place phone calls over their Internet connection, AppleInsider has learned.

People familiar with recent builds of the software say voice over IP (VoIP) Internet dialing is just one of several new features in iChat 4.0, which Apple is expected to bundle with the operating system overhaul, code-named Leopard.

The move will pit the Apple-branded video conferencing and instant message software against existing VoIP solutions from the likes of Skype, Google and Microsoft.

Skype, which began as a small software startup in 2003, is largely accredited with popularizing free Internet telephony through its self-titled software application. The Luxembourg-based company was recently acquired by eBay. It boasts a userbase of over 100 million and offers its software in 27 different languages.

Recently other industry heavyweights have looked to get in on the VoIP craze. Just this month, Microsoft added VoIP features to Windows Live Messenger, which will be available to users of its forthcoming Vista operating system. Meanwhile, Google wedged its foot in the door last year with public beta release of Google Talk, a similar software-based service.

If reports pan out, VoIP functionality won't be the only feature of Apple's Leopard to rival similar offerings from both Google and Microsoft. Earlier this month, sources reported that Apple also appears ripe to introduce a geographic mapping solution with Leopard, similar to Microsoft's Virtual Earth and Google's Maps.

The Apple software, which is simply dubbed "Maps," is also rumored to employ GPS functionally. In the future, the Cupertino, Calif.-based company may leverage the technology to help track stolen Macs or iPods, people familiar with the software have said.

A team of Apple executives is scheduled to formally unveil Leopard during the second week of August at the company's annual World Wide Developers Conference. Although Apple has so far referred to the operating system as "Mac OS X 10.5 Leopard," there's a strong possibility that name will change, sources have said.