This is part 7 of the Windows Phone 7 series:

The Windows Phone 7 Application Platform is made with the presumption to help developers create their applications. The main goals of the platform are:

1. A familiar toolset – in order to develop for Windows Phone 7 you don’t need some new development environment. Microsoft Visual Studio 2010 is used as a development environment. Moreover, most of the Windows Phone 7 controls have the same functionality as their corresponding controls in Silverlight.
2. A consistent API – Microsoft .NET Compact Framework is used to develop applications. This framework is consistent with the desktop Microsoft .NET Framework. Keep in mind that Windows Mobile’s .NET Compact Framework is not the same as Windows Phone 7’s .NET Compact Framework.
3. An isolated space for each application – Each application has its own isolated space (known as Isolated Storage in Silverlight).
4. Runtime services to connect to web services on the cloud or third party Windows Communication Foundation (WCF) services – this makes Windows Phone 7 part of the cloud. This means you can work with the same data across multiple devices. You can use Xbox LIVE to play with other people, location services to get position specific information such as weather forecast or nearest restaurants.
5. The Windows Phone Marketplace – Within Marketplace’s help you can distribute your application to all Windows Phone 7 customers.

Windows Phone 7 supports two technologies – Silverlight and XNA. These two technologies cover all the users' needs – Silverlight is used for rich applications and utilities, while XNA is used for gaming. This gives your phone full functionality – work and entertainment.

By using Silverlight you can provide high-quality text, graphics, media, animation, and data binding that run on multiple platforms and browsers. This is a powerful technology that combines user rich interface without functionality compromises.

XNA is a Microsoft game platform, that supports 2D and 3D gaming. By using XNA you can write high-technology games for PC, Xbox 360, Zune and Windows Phone 7. Combined with cloud services, it can turn your phone into a mobile multiuser gaming platform.

Windows Phone 7’s architecture platform consists of four main components – Runtime, Tools, Cloud and Portal services.

Source: MSDN © 2010 Microsoft Corporation. All rights reserved.

All this is provided by Microsoft. This is more than enough to start developing.

What do we need to start developing

There is only one thing that you need to start developing for Windows Phone 7 - Windows Phone Developer Tools Beta, which includes Visual Studio 2010 Express for Windows Phone Beta, Windows Phone Emulator Beta, Silverlight for Windows Phone Beta, Microsoft Expression Blend for Windows Phone Beta and XNA Game Studio 4.0 Beta.

Microsoft also provides us with a very useful series of videos named "Windows Phone 7 Jump Start Sessions". The total time of all the 12 videos is about 12 hours! That's more than a "Jump Start" :) You can find the session materials here.

Note that for now the only supported language is C#.

The latest news tells us that the final version of the Development Tools for Windows Phone 7 will be available on 16th of September.

So everything we need is here. It’s our mission to make Windows Phone 7 a phone that every customer will want.