No sooner had I started talking about building an app to help people find their local evangelists, than someone at Microsoft beat me to the punch:

http://msdn2.microsoft.com/en-us/events/bb905078.aspx

Now you can find the Evangelists in your area quickly and easily.  I personally think that they should default to your local area evangelists (either based on your profile, or perhaps the data coming in from your browser) but anyway...  Enjoy!