I had a great time tonight at the Findlay .NET User group! Thanks everyone that battled the weather to come out and hear me talk about the ASP.NET MVC Framework. As promised, I have posted the route constraint to allow only alphabetical values to be accepted as valid input for the display named message.
routes.MapRoute("Message",
"Message/{action}/name/{Name}/",
new { controller = "Message", action = "HelloWorld", name = "" },
new {name="[a-zA-Z]+"}
);
I apologize about the lapse in memory — The regular expression needed a + at the end to signify that it was more than one character whoops 
For more information on Routes check out Justin Etheredge's post on routing