Today’s Silverlight 4 Tooling Release for VS 2010 includes a bunch of nice new features.  These include:

Support for Silverlight Out of Browser Applications and Elevated Trust Applications

You can open up a Silverlight application’s project properties window and click the “Enable Running Application Out of Browser” checkbox to enable you to install an offline, out of browser, version of your Silverlight 4 application.  You can then customize a number of “out of browser” settings of your application within Visual Studio:

Notice above how you can now indicate that you want to run with elevated trust, with hardware graphics acceleration, as well as customize things like the Window style of the application (allowing you to build a nice polished window style for consumer applications).