At MIX 06 WPF/E was announced Tim Anderson (ITWriting) posted a thorough story highlighting Microsoft’s attention to user experience along with technical insight to the capabilities of WPF/E.
He talks about how "Under the hood, XAML applications are also .NET Framework applications."
He also elaborates how there is wide variety of support "WPF/E has broad scope. It is aimed at devices as well as desktop or notebook computers, though the device support will follow later than the initial Web release."
Including Microsoft will support many "platforms directly, including Safari and FireFox on the Mac, Opera, FireFox and IE on Windows, and possibly Linux and Solaris. "
A brief comparison of Flash vs WPF.
You can see more demos at: http://blogs.msdn.com/mharsh/archive/2006/03/23/559106.aspx
How to write your own XAML? XAMLON
Or there is a tool with the Microsoft Windows SDK. "To get developers started with XAML, Microsoft provides a useful tool known as XAMLPad. XAMLPad is a XAML editor that allows you to quickly preview your UI. To use XAMLPad, go to Start, choose Programs, choose Microsoft Windows SDK, then choose Tools, and finally choose XAMLPad."