For those of you that are ASP.NET 2.0 junkies (myself included), you can check out this white paper describing the layout, usage and development of the new Provider Model model within ASP.NET. The white paper has 9 sections with this break down:
Introduction to the Provider Model
Membership Providers
Role Providers
Site Map Providers
Session State Providers
Profile Providers
Web Event Providers
Web Parts Personalization Providers
Custom Provider-Based Services
Hands-on Custom Providers: The Contoso Times
I've yet to look through them all, but from reading the intro, this looks pretty sweet!