HRTF
Sites with Head Related Transfer Functions (HRTFs) - or more correctly Head Related impulse Responses (HRIRs) available:
Neural Systems Lab at University Maryland
Waisman University
IRCAM
CIPIC at UC Davis
KEMAR dummy head recordings, MIT, 199x
Acoustic Information Systems Lab, Japan, 2001
European Acoustics Association AUDIS catalogue, 1998, non-commercial use ok, but costs 66 EURO. See also here.
ITAKURA, Japan, 1999-2003