this is a great series from the CBC in the 70's
http://archives.cbc.ca/programs/1564/
there are 22 vids to watch.
the biggest rule you need to know for hockey skating is knees over your toes and shoulders over your knees, Elbows up high, head up.
when you take a stride leave your knees bent extend with the pushing leg then when you bring your legs back place them back under you in stance. you kind of want to feel like you are on your toes all the time while you are getting started.