As we saw in the first of this multi-part series on advanced mobile applications, a war for the corporate palmtop is brewing. It promises the same religious ferocity as the one that saw the Windows PC win out over the Apple Macintosh on the desktop 20 years ago.

For the growing number of companies that view mobile applications as a strategic priority, the question arises: which is the best operating system platform on which to develop or deploy mobile applications? The main contenders are: Symbian, the operating system used on many smartphones, including those from Nokia; Research in Motion's BlackBerry; and Microsoft's Windows Mobile.

We'll start in this article with a closer look at RIM's BlackBerry platform.

Some analysts will tell you the war for the palmtop is already won, while others say it has a long way to go. But even if one platform ultimately dominates, the losers are unlikely to go away anytime soon.

"There is a battle," says the always contentious Ken Dulaney, vice president of mobile computing at Gartner. "But I think at this point the game is over. Microsoft has won."

Dulaney concedes that market share data has yet to reflect Microsoft's ascendancy. The data shows either RIM or Symbian in the lead, depending how you define the market, "But our job is to say where we think it's going," Dulaney says. "And what we see from our customer base is that that's where it's going."

Yet his colleague William Clark, vice president of research for wireless and mobile at Gartner, believes we're still only in the early stages in the war for the palmtop. While the arrival of Windows Mobile 6 later this year may propel Microsoft into the lead, Clark believes many enterprises will delay making an exclusive choice, and probably should.

"If enterprises are considering making an investment today," Clark says, "they had better plan on [there being] diversity for quite some time."

Nathan Dyer, Yankee Group's analyst for the enterprise mobility group, is inclined to agree. "I think the market is big enough to accommodate three, maybe four leaders," Dyer says. He includes Java as a leader, even though it is not a standardized platform like the other three.

Still, Microsoft is the horse to beat, Dyer says. "The onus is on [the others] to keep up with Microsoft, even if they have greater market share today." That applies to RIM, the most successful mobile e-mail platform, in spades. Indeed, it may have the most to lose.

Dulaney says RIM has done a good job developing a strong platform and concedes that customers are generally pleased with their BlackBerry systems. But one glaring weakness he sees in the platform is that it's effectively available only on hardware from RIM. Companies that choose Windows Mobile or Symbian will have a choice of many hardware vendors.

RIM has licensed its software system to other hardware manufacturers under the BlackBerry Connect program, but Dulaney calls the program "a disaster." Hardware partners don't get the latest versions of the software, he says, and as a result can't compete effectively against the RIM devices.

Dyer too praises RIM, but also has reservations. "It's supported by the most U.S. cellular carriers," he points out. "It's a very secure platform, optimized for a great mobile experience. And one pro in the U.S. is that it has the largest installed base of smartphones and PDAs of any platform."

The one con, Dyer says, is that RIM doesn't have a very large developer community, and not many pre-built applications are available.

This is a criticism analysts have been leveling at RIM for a few years, but Jeff McDowell, the company's vice president of global alliances, takes issue. RIM has two developer programs, McDowell explains. One provides software resources, online white papers and basic technical support. He claims there are tens of thousands of registered users.