转：http://blog.sina.com.cn/s/blog_5eaba14c0100ikhl.html什么是SDK?
SDK 就是 Software Development Kit 的缩写，
中文意思就是“软件开发工具包”。
SDK: Software Development KitWe have not released a new SDK for Windows Mobile 6.5. The Windows Mobile 6 Professional SDK orWindows Mobile 6 Standard SDK are required for Windows Mobile 6.5 application development.DTK: Developer Tool kit 开发工具包The Windows Mobile 6.5 Developer Toolkit (DTK) is not an SDK! The DTK contains emulators, gesture APIs, and samples useful for developing Windows Mobile 6.5 applications. You will still need to install Visual Studio and the Windows Mobile 6 SDK prior to running the toolkit installer.DRK: Developer Resource Kit 开发资源包The Windows Mobile Developer Resource Kit (DRK) is an offline DVD copy of the most useful and relevant Windows Mobile application development tools and resources. Traditionally the DRK does not contain any exclusive content, in that nearly everything on the DRK is available for download online. This time we are pleased to publish the Windows Mobile 6.5 DRK with several sample chapters of Microsoft Mobile Development Handbook from Microsoft Press (Wigley, Moth, and Foot).We hand out free copies of the DRK at several conferences and developer events throughout the year.