When writing the basics series, the UV Mapping series was proven to be the most complex. After a successful class experience, I've written a whole new series that develops the topic even in more detail. More examples, more "why's", and more unwrapping methods are explained. This series is a must. The first book is released now to L$60 during the weekend.
Also, we talk here about moving to Blender 2.71. Check that link out for the most important changes in the interface :-)