Fabrice has been working on a number of really cool extensions to ASP.NET 2.0.
One of them is called "PageMethods", and provides a really nice way to perform strongly-typed, clean, url based navigation (with compile-time checking) across an ASP.NET application. You can read about its features and browse a tutorial on how to use it with VS 2005 here. Fabrice has a royality free license and you can download it for free.
Here is a pointer to a discussion group he just setup for it today.
Very cool stuff. Special thanks to Fabrice for building it!