I saw that movie, and if I remember correctly it was Inuit throat singing. Although they have both been dubbed "throat singing," - they're very different styles in terms of how the tones are pronounced. What they're doing involves a form of rhythmical exasperation, really, whereas what I'm doing involves isolating harmonic tones in my voice. Essentially, in that video, the sound I was making is a very sharp sounding "EEEEEEEEEEEEE" sound that simply sounds harmonic because I have actually muted other tones while emphasizing others. A lot of it has to do with resonance in the epiglottis, the ventricular folds, and the nasal cavities. However, it is certainly not limited to that. Throat singing, or overtone singing, carries numerous forms. In Tuva, they practice Karygaraa, Sygyt, and Khoomei - traditionally, however other rare forms exist in other parts of Tuva. Mongolian Throat singing technically differentiates from Tuvan throat singing, but the differences are so minute to the average ear that people rarely discern the two.
here's some Inuit singing
save some time, click the 0:30 mark
http://www.youtube.com/watch?v=qnGM0BlA95I
