Windows Phone 7 Gets Visual Basic BoostWindows Phone 7 Gets Visual Basic Boost

Microsoft has released tools for building Visual Basic applications for Windows Phone 7, a move that could produce a significant number of applications for the new smartphone operating system.

Microsoft made the VB add-on for the Windows Phone Developer Tools available for download Monday. The add-on can only be used to create Silverlight applications for Windows Phone 7.

Only developers with Visual Studio 2010 Professional, Premium or Ultimate editions can use the new tools. The add-on does not support Visual Studio 2010 Express for Windows Phone.

In addition, the new VB tools do not support applications built on Microsoft's XNA Framework, which is a set of tools and runtime environment for computer-game development. Microsoft did not say whether it planned to provide VB support in XNA in the future. However, the latest add-on is an "initial release" with updates to follow.

Millions of developers program in Visual Basic .Net for Windows, which opens up a large potential source of applications for WP7. Microsoft could use some help in beefing up the number of apps available for the smartphone. While Apple offers more than 300,000 apps for the iPhone, Microsoft's online marketplace has less than 2,800, according to WP7 Applist, a Web site that tracks such applications.

While Microsoft hasn't released sales numbers for WP7, there are early indicators that consumer reception has been disappointing. According to U.K. retailer MobilePhones, only 3% of its sales are coming from WP7, and Android-based phones are outselling WP7 devices 15 to 1.

TheStreet.com has said only 40,000 consumers bought WP7 devices on launch day in the U.S. on Nov. 8. However, Microsoft has not confirmed that number. By comparison, Apple sold 1.7 million iPhone 4s the first three days it was available after the June 24 launch.