A good, hands-on tutorial for creating a DAL for your ASP.NET application

Scott Mitchell has written a very good tutorial about ASP.NET application development and the crucial step of accessing the data in a proper way. The examples are in VB.NET.

Of course, for very simple web applications, a DAL (Data Access Layer) might be overkill, but it is better to get into the habit of having a proper foundation for your applications as they have the tendency to grow.