The process involves breaking the model up into several parts that can be flattened, and then stitching them back together again. It's not something that can easily be explained in a few steps, and each model always presents different challenges. I've been thinking of starting a tutorial (it will take some time), but I'm not sure whether it would be best to do an animal or a human figure. I go between UV Mapper Pro and Deep UV to do my UV mapping (I think this is how the Millenium figures are done).