Finding and Tracking People
  Much research on this topic sees it as a problem in probabilistic
inference.  I think the significance of  the probability and
algorithmic aspects of
this problem is much overrated; the major difficulties are vision
problems.  One has to reason about what things look like, reason
about appropriate
feature representations, then determine how to find instances of the people in each frame.  
I wrote an extensive review of this area (nearly 500 citations in it!)
David A. Forsyth, Okan Arikan, Leslie Ikemoto, James O' Brien, Deva Ramanan,
    Computational Studies of Human Motion: Part 1, Tracking and Motion Synthesis, Foundations and Trends¨ in 
Computer Graphics and Vision
Volume 1 Issue 2/3 (255pp), 2006 
My sometime student, Deva Ramanan, has been especially active in this area, and his work is worth reading closely.
Current students who have worked in this area include: Alex Sorokin, Duan Tran and Du Tran
Finding People
  - M.M. Fleck, D.A. Forsyth and C. Bregler,  ``Finding naked
    people,''  Proc.  European Conf. on Computer Vision , Edited
    by: Buxton, B.; Cipolla, R.  Berlin, Germany: Springer-Verlag,
    1996. p. 593-602 
                     
                     
                     
                     
                              
-  Forsyth, D.A.; Fleck, M.M.  ``Identifying nude pictures'',   Proceeding. Third IEEE Workshop on
    Applications of Computer Vision.  103-108, 1996.
      
- Forsyth, D.A. and Fleck, M.M., ``Body 
Plans,'' Proc. CVPR-97, 
678-83, 1997.
- Forsyth, D.A. and Fleck, M. M., ``Automatic Detection of Human 
    Nudes,''  International Journal of Computer Vision ,  32 , 1, 63-77, 
    August, 1999 
   
- Ioffe, S. and Forsyth, D.A., ``Learning to find pictures of 
    people,''
    in  M. S. Kearns, S. A. Solla, and D. A. Cohn, editors,  Advances in Neural
      Information Processing Systems 11 , MIT Press, Cambridge, MA, 1999
- Duan Tran and D.A. Forsyth, "Configuration estimates improve pedestrian finding," Proc NIPS 2007.
 
Tracking people
- S. Ioffe and D.A. Forsyth,  ``Human tracking with mixtures of trees,''   Proc. IEEE InternationalConference on Computer Vision , 
pp. 690-695, July, 2001
  
-  Ramanan, D. and Forsyth, D. A. 
    "Finding and tracking people from the bottom up"
     in Proceedings of Computer Vision and Pattern Recognition (CVPR), Madison, Wisconsin, June 2003. 
- Ramanan, D. and Forsyth, D. A. "Automatic Annotation of Everyday Movements" Neural Info. Proc. Systems (NIPS), Vancouver, Canada, Dec 2003.
 poster  (Longer technical report version)
      
- Ramanan, D. and Forsyth, D. A. "Using
Temporal Coherence to Build Models of Animals" Intl. Conf. on Computer Vision (ICCV), Nice, France, Oct 2003. 
    talk slides (talk video  82MB streaming)
    
-   Ramanan, D., Forsyth, D. A., Zisserman, A."Strike a Pose: Tracking People by Finding Stylized Poses." 
Computer Vision and Pattern Recognition (CVPR), San Diego, CA, June 2005              
                   
-   Ramanan, D., Forsyth, D. A., Barnard, K. "Detecting, Localizing, and Recovering Kinematics of Textured Animals." 
Computer Vision and Pattern Recognition (CVPR), San Diego, CA, June 2005.     
                   
    
- Ramanan, D.; Forsyth, D.A.; Barnard, K.;,
"Building models of animals from video"
Pattern Analysis and Machine Intelligence, IEEE Transactions on
Volume 28, Issue 8, Aug. 2006 Page(s):1319 - 1334     
                   
                
                   
                   
                   
                   
                  
- Ramanan,
D; Forsyth, D.A.; Zisserman, A; "Tracking People by Learning Their
Appearance," IEEE Transactions on Pattern Analysis and Machine
Intelligence, Volume 29, no 1, pp 65-81, 2007.