In this article Damon Payne shows how you can build a flexible Navigation framework around Views and even support handy features like strongly typed parameter passing and selecting from multiple implementations when present.
Silverlight 3 ships with a Navigation mechanism. A control that extends Page can be stored inside the Frame control as content, and Navigation from Page to Page is done by specifying the URI of the target Page. This mechanism includes navigation history and the ability to go forwards and backwards through said history. I would, however, like a slightly different programming model around application navigation.