Regular contributor to the ukcider discussion group, Stephen Hayes, has recently uploaded a very useful series of videos on apple tree pruning. They can be viewed on Stephen's YouTube Channel here: http://www.youtube.com/profile?user=stephenhayesuk.
Hampshire based Stephen and his partner Julia, established an orchard of heritage apple varieties in the 90's, and have subsequently amassed a great deal of practical experience in the management of fruit trees, including a number of cider varieties. Short of attending one of the hands-on pruning courses which are run around this time of year, this is the best bit of pruning advice you're likely to find. Stephen has a very watchable style and I can't recommend this series of video workshops highly enough. Whilst there are plenty of books available which go a long way towards explaining the theory of pruning, there really is nothing better than seeing the process in the flesh. I hope that Stephen continues to share his knowledge and experience with us over the coming years.