Skyhook Wireless took a look at what LBS developers are doing for Apple’s App Store, Google’s Android Marketplace and BlackBerry App World and found that few developers distribute apps across all three stores.

According to Skyhook’s February report, there are nearly 6,000 location apps on iPhone, 900 on Android and 300 on BlackBerry, but only 43 of these apps are available in all three app stores. Of the 43, most are free, indicating that developers make their apps cross-platform as a way to increase download numbers, not revenues. Developers that are interested in high revenue tend to focus only on paid apps for iPhone.

In addition, all paid cross-platform apps set different pricing points across each platform. BlackBerry versions are always the most expensive, while iPhone and Android versions are usually set much lower, Skyhook says.

“We were surprised to see so few location apps being distributed across these app stores,” said Kate Imbach, vice president of marketing at Skyhook Wireless. “The iPhone is now the platform of choice for developers who are monetizing via app sales. It will be interesting to see if over time developers can successfully monetize via sales on other platforms.”