I did my O/W cert. (Oct. 2000) through my LDS (Sand Dollar Dive Center, Smith, AL) and it was NASE. It started up in 1982(?) and is HQ'd in Texas, I believe.
They (NASE) catch alot of flack because they give the instructor a lot of leeway. (The opposite of PADI from my understanding). The instructor can choose from several different manuals (i.e. you used Naui, we used "Jeppesen's); different tables (you used PADI, we used modified Navy-Doppler tables). We used some videos, but I don't remember whose they were. Most of the class time was taught by the instructor. We had five class sessions ( 2 hours each), six pool sessions (2.5 hours each) and did four OW scuba dives and one skin dive.
I really enjoyed my OW classes and have signed up to my Advanced classes in July.
There is a good comparison article/chart on scubadiving.com that includes NASE. Do a search on NASE over there.
kd4rfa