Look at "Minimal dialog-based WIN32 application" - it has some code to do some other stuff but the basic skeleton is the same. Here is another example of the minimal code:
This may be a bit of an odd recommendation, but also look for tutorials on how to create keygens - the majority of those are dialog-based since the interaction fits the model perfectly - when a button is clicked, read one or more text fields, do some computation, write the result to another text field.
After I spent $59.99 on Petzold's "Programming Windows 95", I ended up just using it as a reference and instead went through TheForger's (from #winprog) tutorial: http://www.winprog.org/tutorial/
Are there any tutorials/articles on how to do it?