At my Silverlight 3 talk last week, I got a question about if it is possible to share Isolated Storage between the Silverlight client and the Out-of-Browser client.
This is working out-of-the-box in Silverlight. If you store some information to the Isolated Storage in your Silverlight client while running in your browser, it will be available to your out-of-browser client as well.
It have created a small sample application that can run out-of-browser to demonstrate it. It can be downloaded here.
Happy Coding!
thomas martinsen 
I ran in VS2010 .net 4. Saved ‘qwerty’ in web app. Installed the client locally. Hit retrieve and got nothing. Shouldn’t I have seen ‘qwerty’?