By Prince McLean

Published: 11:00 PM EST (08:00 PM PST)

The launch of the iPad is helping Apple's iTunes App Store to retain developers' interest while preventing them from exploring alternative marketplaces for mobile software.

A report by the Wall Street Journal cited Social Gaming Network, an App Store developer, as saying that 90% of its employees were currently working on iPhone OS apps.

The fact that RIM, Palm, Microsoft, and Google have also opened their own mobile application stores has not automatically created the same level of success. "You have to choose your battles wisely," SGN chief executive Shervin Pishewar told the Journal.

The new iPad, the Journal said, "is boosting developer interest in Apple's store because the device is set to expand the audience for apps and paves the way for developers to introduce new innovations."

iPad + iPod touch + iPhone

Analysts are estimating Apple will sell anywhere between 5 to 10 million iPad units in its first year. Those numbers will add to the existing installed base of iPhone OS devices, which now number more than 70 million.

Just as the iPod touch has served to bolster Apple's software position on the iPhone in a way that rival smartphones can't match, the iPad will also expand the App Store reach and level of sophistication in ways that rivals' tablet devices won't.

Google hopes to release tablet-form factor devices later this year using the Chrome OS, reliant upon both web apps and Flash content. But Chrome OS won't run today's existing Android apps.

Similarly, Microsoft has floated Tablet PC, UMPC and most recently Slate PC designs, but these are all based on its desktop Windows platform, and don't support either its now mothballed Windows Mobile 6.x platform of mobile apps nor its planned Windows Phone 7 devices designed to run Silverlight and Flash apps.

Microsoft's futuristic Courier product concept is expected to one day merge with WP7 and the Zune HD to result in a cohesive development strategy like the one Apple created with iPhone 2.0 back in 2008, but even if that can happen by early next year, it will be years late to the App Store party.

Problems facing alternative mobile software markets

Palm's webOS launched its mobile software Catalog last year, but that was still too late to attract enthusiasm from many developers. Google's Android Marketplace opened back in 2008 just a few months after Apple launched the App Store, but even it has seen a difficult time keeping pace with Apple's level of interested users and developers.

In addition to having failed to capitalize on the importance of building out an application strategy early and comprehensively, other platform vendors have also made it much more difficult for their developers to build apps that can run seamlessly on their products.

The Journal noted, "Apple's devices also have key features that help play up apps, such as high-quality color touch-screens, accelerometers and relatively fast processors." While many Android phones offer fancy hardware features, each new model introduces a new mix of specifications in terms of screen resolution, processor speed and available hardware features. This complicates the task of building apps that work and look good across all those devices.

Many Android phones (as well as smartphones from other alternative platforms) are also stuck running the version of the OS they shipped with, thanks to apathetic mobile operators who lose interest in supporting upgrades after making the sale, if not for actual limitations in the hardware that make upgrades impossible.

Even developers who sell their apps across a wide number of platforms focus their attention on the iPhone. The Journal cited Pandora Media's chief strategy officer Tim Westergren, who sells a version of his company's Internet radio app for Android, Palm's webOS, and RIM's BlackBerry in addition to the iPhone, as noting that his company gets almost a third of its new registrations from the iPhone, even though iPhone 3.0 currently prevents Pandora from running in the background.

Despite that hurdle and the interest other platforms are making for his attention, Westergren told the Journal, "if there's a new opportunity on the iPhone, we would prioritize it."