SAN FRANCISCO — Apple Inc. launched a version of its Safari Web browser for Windows-based PCs on Monday, adding yet another tentacle to its multi-pronged encroachment of Microsoft Corp.'s turf.

"Safari is another Trojan horse that introduces an innovation of Apple to the Windows community and entices them to the Mac platform," said Tim Bajarin, an industry analyst at Creative Strategies, a technology consultancy.

The free program is the latest move by Apple to expand its reach beyond its Macintosh computers and, at the same time, attract new converts to its products. The upcoming iPhone seeks to be another draw.

Previously, Apple made its iPod media player and iTunes Store compatible with Windows, introducing Apple's touch to millions of Microsoft Windows users who don't own a Mac.

The slickness of its gadget designs notwithstanding, the key to Apple's success and reputation for ease of use is its software and how well it integrates with its hardware.

"There are a lot of connections between our products and here's one more," Apple senior vice president of worldwide marketing Phil Schiller said of the Windows-version of Safari in an interview. "And the more people who like our applications, the more it might mean they'll buy other products from us."

The strategy is apparently paying off. Mac sales have grown significantly over the past two years, pushing its slice of the PC market in the United States from 3.5 percent in 2004 to 4.9 percent in 2006, according to IDC, a market research firm.

About half of the Macs sold today in Apple's retail stores are to people new to the Mac platform.