One question I get asked a lot while talking about Silverlight is if there are Flash to Silverlight (currently in version 2 beta 2) conversion tools available. The quick answer is there are not many such tools in the market at present. But you can find some from the Internet such as Michael Swanson's SWF2XMAL.
I recently came across Scott Hanselman's interview with Rick Barraza, an Experience Architect from Cynergy, and Bryan Perfetto, a Developer from Inxile, in which they chat about how and why they ported the popular Flash Game LineRider.com to Silverlight 2. It took them several weeks to port the application from coding, debugging and testing.