Here's a link to a very informative (and free!) video on barotrauma (pressure related ear injuy). The speaker is Dr. Edmond Kay, a GP and dive doc in Seattle. This link may have already been posted, not sure...
http://www.uwtv.org/programs/displayevent.asp?rid=789
http://www.uwtv.org/programs/displayevent.asp?rid=789