2.1. XAML Prerequisites
Although XAML is designed specifically for Windows Vista, it's also available on Windows XP and Windows Server 2003, given that certain system requirements are met. This makes it possible for developers to become familiar with XAML and the WinFX SDK before Windows Vista is officially available.
XAML can be used to develop applications on the following operating systems:
On Windows XP SP2 and Windows Server 2003 SP1, you will first need to install the WinFX runtime, which contains, among other things, the Windows Presentation Foundation (Avalon). Regardless of the operating system you choose, you'll need to install the WinFX SDK. The SDK contains the libraries, build tools, and documentation necessary to begin developing user interfaces with XAML. Depending on the operating system you choose, the WinFX SDK may also have prerequisites that must be met.