...And it's round three.
A membership provider is a part of ASP.NET 2.0 that has the ability to do anything you want with member interface and manipulation of member information. The provider allows you to use predefined web controls for functions such as login, add member, and password retrieval; it even allows you to specify a database to interact with.
I only became aware of the membership provider this week but it's very useful if you learn to use it. Of the resources I've looked through there are two books I would recommend, Introducing ASP.NET 2.0 and Expert ASP.NET 2.0 Advanced Application Design have both been very helpful.
Enjoy the Labor Day weekend!