http://www.adefwebserver.com/DotNetNukeHELP/DNN_Module4
I used a "Guest Book" as an example because it covers most of the
functions you need in a module, "Select", "Delete", "Update", and
"Insert".
The tutorial shows you how to bind a Grid View to a data source using
the DotNetNuke DAL (Data Access Layer) and Object Data Sources.
Using the techniques in this tutorial you will be able to bind your
Grid View and Form View controls directly to your DAL "controller
class". The only code you will need in the "code beside" will be a few
lines of code to inject things like the current "ModuleId" (needed for
entries into the database because you want to store which module
instance the data came from. A person could place multiple instances of
the module on a single page of their DotNetNuke site).
These techniques save a massive amount of code that you would have to
write if you wrote the exact same module in ASP.NET 1.1. I estimate
70%+ reduction in code.