As part of an ongoing series of revelations about its upcoming Windows Phone platform, Microsoft on Monday discussed the developer story for the platform. This information follows the initial Windows Phone announcement last month at Mobile World Congress and some game developer info at the Game Developer Conference earlier this month. And Microsoft plans to provide some enterprise-oriented announcements in the future as well.

"Windows Phone 7 Series was designed to generate incredible opportunities for developers and designers to quickly and easily deliver compelling applications and games," said Microsoft Corporate Vice President Joe Belfiore. "With the best developer tools, an established ecosystem and marketplace, and a path for developers to use their \\[existing\\] skill sets, we are delivering an application platform that is simple, powerful and inspiring."

Monday's announcements included providing developers with information about the tools they will use to create Windows Phone applications. These tools include the Visual Studio 2010 development environment with a Windows Phone add-on, the Expression Blend user interface designer tool, and new versions of the Silverlight and XNA development frameworks.

Microsoft is providing these Windows Phone developer tools for free as well, and the company made a prerelease version of the tools, including a Windows Phone software emulator, available for download on Monday. The company also discussed its plans for Windows Phone Marketplace, which will be available on all Windows Phone devices as well as on the PC via an updated version of the Zune software. Any paid Windows Phone apps can be made available as a free trial version via the Marketplace, the company said.

In various meetings throughout the day, other interesting aspects of Windows Phone 7 were revealed. Microsoft told me that it would "own" the entire Windows Phone experience, and would not allow its partners to replace the UI, as they had with Windows Mobile. This also means that Microsoft will provide a Windows Update facility for Windows Phone, so that wireless operators can't prevent users from getting various software updates and new functionality.

The company is also locking down the application deployment process with Windows Phone: Now, third party sites will not be allowed to provide users with Windows Phone applications. Those applications will have to come directly via Windows Marketplace only. (An exception for corporate applications will be announced later, the company told me.)

One potentially sticky area is multitasking. While the company claims that Windows Phone will support "full multitasking," first generation third party applications will only be able to use a push notification system, similar to what Apple promised to iPhone developers. (Microsoft's Windows Phone applications will support native multitasking capabilities, however.) The company plans to open up the system's multitasking functionality to third party developers over time, I was told.

Tomorrow, Microsoft will reveal some developer information about Internet Explorer 9, the company's next web browser. As always, please stay tuned to the SuperSite for Windows, where I'll be providing ongoing news from MIX'10, including a Day 2 keynote liveblog.