Research In Motion is keeping pace in the mobile browser race with the purchase this week of Torch Mobile, maker of the WebKit-based Iris smartphone browser.

Torch Mobile, a WebKit developer that makes the Iris mobile browser, announced Monday that it has been acquired by RIM for an undisclosed sum.

Already, observers are calling RIM’s acquisition of Torch Mobile prudent on several levels, and is the first step toward making good on delivering an improved BlackBerry browser by next summer, William Stofega, mobile analyst at IDC, told InternetNews.com.

“First, RIM needed to upgrade in the browser area, and the sooner the better. Plus, the whole idea of WebKit being an open platform means many developers can use it,” Stofega said. “I also think RIM is doing the right thing by purchasing the company outright because it’s a complex process. Owning the company makes it easier to make sure everything is backwards-compatible, and so on.”

WebKit also powers Safari, the browser in use on Apple’s iPhone, as well as the browsers offered with Palm’s Pre and Android-based handsets.

Given the booming success of WebKit. the move by RIM may help it keep the BlackBerry’s features on par with its rivals.

The news comes as part of a larger effort by handset makers to rev up their their software as they gun for dominance in the lucrative smartphone market.

On June 17, the day after it launched the iPhone 3GS, Apple updated its OS to version 3.0, with 3.1 due out in September. Palm, which offered the Pre on June 6, just opened up its new platform, webOS, to developers.

Google-backed Android saw its first major upgrade in May, with “Cupcake,” or version 1.5. Android is also is slated to be updated by the fourth quarter to version 2.0, dubbed “Donut,” while Samsung, Motorola, Acer and HTC plan releases by the end of the year.

Meanwhile, Microsoft and Nokia recently forged a partnership that will begin by porting Office Mobile applications to run on Nokia’s Symbian operating system. The deal, with will see Office first appearing on Nokia’s Eseries enterprise devices, marks the first time that Microsoft has ported its Office applications to run on any smartphone operating system besides Windows Mobile.

As for Torch Mobile, the acquisition will mark the latest step for its Iris smartphone browser, which is currently available for platforms including Windows Mobile and the Nokia-owned embedded Qt framework.

“Our team of developers will join RIM’s global organization and will now be focused on utilizing our WebKit-based mobile browser expertise to contribute to the ongoing enhancement of the BlackBerry platform,” Torch Mobile said in a statement on its site.