Shaderific is a great iOS application for OpenGL ES shader learning. The app provides the source code for the vertex and fragment shaders for 18 built-in demo shaders, and it allows the creation of new ones. Many 3D objects (including the required teapot) are available, and material and lighting can also be set. There is a free version that lets us try it out, but the changes are not kept once the app is closed.
Since I’m one of the authors of a couple of chapters in this book I’ll refrain from commenting on it. Check out the companion site, it is full of information, includes 5 sample chapters and all the companion source code.
Ray Wenderlich’ssite has posted an OpenGL ES 2.0 for iPhone Tutorial for beginners. It starts from scratch, describing how to setup a project and goes all the way till drawing a 3D rotating cube.