You will find loads of examples online, i have read the DNN books and even tried some tutorials myself.  Last night i went through a tutorial on how to make a DNN module and I was amazed at how easy, quick and simple it was.  I thought i was using DNN 4.9.1 but my visual studio had version 5.0 , i just used the default SQL/Express

Some how this tutorial conveyed the simplicity in developing DNN modules which I had not picked up on before.  I have already strated on two modules which I was going to buy, but i now think I will have a go a developing my own module.

here it is , its one page long short and sweet.  Presentation of your module is done in the .ASPX , capture the data from Webform to the .VB/.CS file and call to stored procedures in the Database.

If you follow the instructions on the page http://freedotnetnukemodules.com/Tutorials/BrowserInfoV10/tabid/60/Default.aspx

It will give you an understanding hopefully of how to get data from .NET 2.0 framework,  this example is just reading data.

To work on it a bit, try extending it, add some new controls from the toolbox , build a simple form that has labels and text boxes, read how to capture the values from the textboxs and store them temporay using the code behind page and then pass them maybe to a method/function which calls a stored procedure like UpdateTable

its pretty straight forward if your familar with OO Programming.

I also recommend these HowTo Videos very helpful, short and sweet to.  They get straight to the point.  Not directly related but I had been watching them over the last few days and they have really helped me understand and get a lot more out of the DotNetNuke framework.  

Im starting to extend my own web sites a lot better now. 

http://windowsclient.net/learn/videos.aspx

The only issue I had when following the tutorial for making the module, after i selected the Manifest file and went to a page and added my module, the error message was telling me that the module folder , inside the web sites App_Code folder was not there.  The code was looking for a folder that was named YourCompany.MyModule

So i went to my web site App_Code folder and renamed the MyModule folder to YourCompany.MyModule and then build the project and refreshed the browser the module was working. 

Now i have extended and added my own text box and lables, populated them with data, sent data to ther web forms and read and wrote to the database. 

hope it helps you