The production version of the Windows Phone 7 development tools will be released 16 September with the online applications store due to open in early October. The latter date could indicate that the first handsets with the radically redesigned mobile operating system might be announced about the same time.

The production version of the toolset is important partly because it shows Microsoft's ability to meet development milestones and partly because it assures developers they now have a stable development platform. Microsoft says that so far the tools have been downloaded more than 300,000 times.

A major remaining milestone is the final production version of the OS itself, the one that will actually appear on new smartphones this autumn. Developers can expect some additions and tweaks with the final tools release, according to a blog post by Brandon Watson, Microsoft director for Windows Phone.

"The final tools will likely have some minor breaking changes from the Beta tools, so developers may have to fix some bugs that arise," he warns. "The final tools will also include several highly requested Silverlight controls, which will make it even easier for developers to deliver high-quality Windows Phone 7 experiences. Also in the Sept. 16 final release, the panorama, pivot and [Microsoft] Bing maps controls will all be available to drop into applications."

Current Windows Phone 7 code will have to be recompiled with the final tools when they're released.

The current beta version of the developer tools includes several elements: Visual Studio 2010 Express for Windows Phone, the Windows Phone Emulator (a PC program that mimics the look and feel of a handset), Silverlight for Windows Phone (intended for rich Internet applications), XNA Game Studio 4.0 Beta release (for game applications) and Microsoft Expression Blend for Windows Phone (a graphical application design tool).

A full set of resources and links is available online. From the first "pre-beta" release of the tools at Microsoft's MIX2010 conference in March, many developers have been impressed with the quality of the code, including the all-important emulator, which for months was the only way to try out software written for the new platform. In July, Microsoft began shipping more than 8,000 prototype handsets from its hardware partners to selected developers around the world, giving them a chance to actually see how their applications and games performed on a real device.

The new Windows Phone Marketplace, an online application catalog that's tightly integrated with the operating system on each handset, will play a critical role for both developers and users. At its TechEd conference, Microsoft unveiled new policies and practices, and laid out the submission and approval processes for application developers. Applications submitted to Marketplace will go through a testing and certification process.

Windows Phone 7  includes a Marketplace "hub" a dedicated area that's tightly integrated with the online site. Users flick through the handset's touchscreen to reach the hub, and can see the newest apps, a featured app, search based on various criteria, and pay for and download apps directly with their phone. No additional software is needed.

Microsoft also released an updated set of Marketplace policies via a PDF file. Watson's blogpost promises that a "limited Beta test cycle" of the application submission and certification process will be launched "in the coming weeks." Finally, he revealed that Microsoft is making unnamed but "significant changes" to the developer portal site, based on comments and requests from developers. To submit Windows Phone applications, developers must register online.  

Microsoft also recently unveiled a 12-episode video training series for Windows Phone.  The "Jump Start" series is by Microsoft MVPs and Microsoft Press authors Andy Wigley and Rob S. Miles. Wigley recently ported the open source Perst object-oriented database from McObject to Windows Phone 7, creating the first on-device DBMS for the new OS.