I've just started working with Maemo and its giving me a headache searching for beginner's information.
This is how I think its best to study, though I haven't gone over all of the material:

1. The first useful guide is the beginner's guide that nokia is hosting (45 minutes presentation) that gives you the theory behind Maemo apps.
2. Go to the developer's guide, Start with "Graphical UI Tutorial" category and start learning about GTK+ (if you're not going to use Qt), I think its more logical to start here because you start with looking at code, and this is the most basic code you need to know.
3. Check out the examples, you can create a new C project with ESBox and use the examples template(you learn about ESBox in #1, I suggest you download the virtual image), then you can see what you've learned in action. Run them all, make sure you understand how they all work.
4. Go over the guidelines for creating your UI, you have many guidelines and general UI info in the first three categories in the Maemo 5 Developer's Guide, they should give you a general idea for what kind of tools you have for building maemo apps.
5. Go to back to developer's guide and go over everything else, like d-bus and the libs, learn more about what they are and how to use them.

I'm not an expert at all but this looks logical to me. like I was tought C#, first I started with hello world, then I learned about the theory behind. Which way do you think is best to start?