I was able to pick up a used Kreg pocket hole jig for a good price and have had a lot of fun trying it out on different projects. In fact, the first time I ever used pocket hole joinery was when I built the guitar case rack. I encourage you to try out the technique, so here are a couple of videos that do a nice job showing how to create strong, concealed pocket hole joints.
This first video does a great job of showing the basics of pocket hole joinery. The demonstration shows the Kreg Jig Master System, but the method applies just as well to other brands and styles of jigs.
Most of the videos I've run across that show how to assemble a joint using pocket hole screws show techniques for face frame construction. In my case I wanted to create a pocket hole joint between panels. This video even shows a couple of tips that would have been nice to know had I seen the video before building the guitar rack.