I found this awhile back (2004), I haven't been able to find a more updated list.
The FAA and the U.S. Air Force have a joint training agreement to offer high-altitude, hypobaric chamber training to civilians for a nominal $35.00 fee. Applicants should contact FAA Aeromedical Education Division (AAM-400), Airman Education Programs, Civil Aeromedical Institute, Oklahoma City, Okla. at (405) 954-4837 to schedule training sessions at any of the following facilities:
Beale AFB, Marysville, Calif.
Brooks AFB, San Antonio, Texas
Columbus AFB, Columbus, Mich.
Fairchild AFB, Spokane, Wash.
Holloman AFB, Alamogordo, N.M
Langley AFB, Norfolk, Va.
Laughlin AFB, Del Rio, Texas
Little Rock AFB, Little Rock, Ark.
Mike Monroney Aeronautical Ctr., Okla.
Offutt AFB, Omaha, Neb.
Peterson AFB, Colorado Springs, Colo.
Randolph AFB, San Antonio, Texas
Shaw AFB, Columbus, S.C.
Sheppard AFB, Wichita Falls, Texas
Tyndall AFB, Panama City, Fla.
Vance AFB, Enid, Okla.
Wright-Patterson AFB, Dayton, Ohio