If you are interested in developing C++ plugins for C4D, then these two tutorials should help you to get started.

Tutorial: C++ Plugin Development for Cinema4D R8
This is a quick tutorial I wrote to try to help people get started with C++ plugin development for Cinema4D R8.

Mini-Tutorial: Building Cinema4D R8 SDK using free VisualC++ compiler
Cinema4D R8 pretty much forces you to use VisualC++ to develop plugins under windows. Fortunately, you can get it for free, legally! This mini-tutorial shows how to set it up so that you can build the SDK plugin examples.