I know I was excited to see this released on Scott Guthrie's Blog

Microsoft has released the source code for thier built in ASP.NET Providers that ship with the product. I can't tell you how many folks I have seen try to get thier brains around how to implement a custom provider only to give up. Having these as examples to work from gives us a GREAT reference architecture for building the custom providers that will allow us to benefit from the ASP.NET 2.0 enhancements that we were told would make our lives so much easier !

Enjoy !!