Front-Ranger -
It could be either, actually (it could be both, also). The two can sound very similar.
I have an old, old Emmons pedal-steel that I'm trying to recondition (I got at a garage sale and it was badly damaged in a fire) that I have played around with for a couple of years, but the playing techniques between the two instruments are quite similar - you fret with either a bottleneck or a steel bar.
http://www.steelguitar.com/I also thought
Wings had a 12-string acoustic in the mix as well, but that could also be 2-6 strings with a very short tape delay.
(edit)
Followup -
http://www.vervemusicgroup.com/product.aspx?ob=disc&src=art&pid=11401I found some info on verve (no scoring) but the playlist seems to indicate that it was a "steel guitar":
Soundtrack
Gustavo Santaolalla (1, 3, 6, 9, 12, 15, 17) Guitar
Bob Bernstein (1, 3, 6, 9, 12, 15, 17) Steel GuitarWillie Nelson (2, 13) Vocal
Emmylou Harris (4) Vocal
Teddy Thompson (5, 10) Vocal
Rufus Wainwright (5, 16) Vocal
Steve Earle (7) Vocal
Mary Mcbride (eight) Vocal
Jackie Greene (11) Vocal
The Gas Band (13)
Linda Ronstadt (14) Vocal
It doesn't specifically state "pedal steel", however.