-Automatic Mood Detection and Tracking of Music Audio Signals (Lu, Liu, Zhang; 2006) (http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1561259)
-Heriberto Avelino from U. of California at Berkeley suggests using standard software to study the pertinent acoustic parameters (hope this translation is accurate), and recommends the followin paper:
Huron, D., Kinney, D. & Precoda, K. (2000). Relation of pitch height to
perception of dominance/submissiveness in musical passages.
-Bill Thompson pointed me towards the Swedish group http://www.psyk.uu.se/hemsidor/musicpsy/ , and a California-based company called MoodLogic http://www.moodlogic.com/ml20features.html. Sound very interesting!
-Joanna Nagy knew about Andreas Friberg's work in Sweden: http://www.speech.kth.se/music/staff/andersf.html
-James W. Beauchamp wrote with great detail. He enlightened me about how this subject is studied in the areas of music perception
and cognition as well as music information retrieval. He also pointed me to both these disciplines annual congresses (ICMPC and ISMIR, respectively). Finally, he remarked from his own research that mood can be something pretty elusive, although there still are inherent qualities in the music that may portray a specific mood (like in film music).
Hope it will be useful, I'd like to thank all the people that have answered so promptly.