If you ever find yourself in need of a basic MVC structure for your application but don't want to get involved with a full framework to do it, you should try out this new screencast from NetTuts.com. It shows you the creation of a simple "tiny MVC" implementation.
It's important for me to note that I'm not advocating that you shouldn't use large frameworks. They absolutely have their places, and I use them often. That said, there are definitely times when they can be overkill for smaller projects. When your only requirement is code organization, it's typically better to scrape together your own MVC boilerplate.
The screencast's about 15 minutes long and it walks you through each step of the way - making the routing, setting up controller handling and working with views. For the impatient, you can also download the source and get started quickly.