"Electric Rain® is bringing new life to Adobe® Flash files within the Microsoft® Windows Presentation Foundation (WPF) and Silverlight platforms with the introduction of Harmony™, the first commercial application for Flash-to-XAML content conversions.
Electric Rain Harmony provides designers and developers with a fast and easy way to convert existing Flash SWF files (graphics and simple animations) into Microsoft-based XAML mark-up for immediate use in the Microsoft WFP and Silverlight (formally WPF/E) platforms."
This tool is yet to be available , one can signup for beta and it'll be a commercial software.There's another tool SWF2XAML developed by Mike Swanson of Microsoft which is free.
The tool developed in Mike's spare time is a fully managed code application. The current version of the tool allows to directly open a SWF file and browse through its frames one by one. When a required frame is found,one can either export a XAML file or copy the XAML to the clipboard for easy pasting. The conversion isn't perfect, and there are many areas for improvement.For common cases, however, it should do the trick.
It requires .NET Framework 3.0. If you're using Windows Vista, its already there.
You can download SWF2XAML here.
UPDATE: Check my new related postConvert SWF to XAML using TheConverted