The following 5 part (under 10 minutes each) presentation from defcon 14
on disk drive repair and recovery was really well done, I thought, as an
introduction to the issues.
YouTube videos:
http://www.youtube.com/results?search_query=defcon+hard+drive+recovery&…
Flash slide show from the presentation is available here so you can play
along at home:
http://web.forensicspeak.com/defcon.htm