At today's kickoff of the MIX10 conference for designers and developers, Microsoft officially announced details surrounding its development platform for Windows Phone 7 Series -- including the availability of a free tools package. As expected, the whole thing is built around XNA and Silverlight.

The full tool package includes:

• Microsoft Visual Studio 2010 Express for Windows Phone
• Windows Phone 7 Series add-in to use with Visual Studio 2010 RC
• XNA Game Studio 4.0
• Windows Phone 7 Series Emulator for application testing
• Expression Blend for Windows Phone Community Technology Preview (available as a separate download)

Developers will be able to take advantage of the following features:

• Accelerometer, an intuitive control that responds to motion
• A Microsoft Location Service to provide developers with a single point of reference to acquire location information
• Microsoft Notification Service for pushing information to the phone, regardless of whether or not an application is running
• Hardware-accelerated video with digital rights management (DRM)
• Internet Information Services Smooth Streaming for the industry's highest quality content viewing experience
• Multitouch
• Camera and microphone support

Microsoft also offered up some details on what will be known as the Windows Phone Marketplace for Windows Phone 7 Series devices. The design has been updated with "a panoramic design and active merchandising" to increase the discoverability of games and apps. Users can also try apps before purchasing them, and payments can be made via credit card or through mobile operators. Like Apple's App Store, the Marketplace will be the only authorized channel for app distribution.