Electric Rain recently announced a new product they're working on called Harmony. This app will take .swf files and convert them to XAML. This tool has the potential to help users with Flash assets ramp-up on Silverlight very quickly. Electric Rain is promising a beta version "soon".
From the product site:
"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."