1) The Yale Face Database B
Contains 5760 single light source images of 10 subjects each seen under 576 viewing conditions (9 poses x 64 illumination conditions).
For every subject in a particular pose, an image with ambient (background) illumination was also captured.
http://cvc.yale.edu/projects/yalefacesB/yalefacesB.html

2) The Color FERET Database, USA
The database contains 1564 sets of images for a total of 14,126 images that includes 1199 individuals and 365 duplicate sets of images.
A duplicate set is a second set of images of a person already in the database and was usually taken on a different day.
For some individuals, over two years had elapsed between their first and last sittings, with some subjects being photographed multiple times.
This time lapse was important because it enabled researchers to study, for the first time, changes in a subject's appearance that occur over a year.
http://face.nist.gov/colorferet/

3) BioID Face DB - HumanScan AG, Switzerland
The dataset consists of 1521 gray level images with a resolution of 384x286 pixel.
Each one shows the frontal view of a face of one out of 23 different test persons.
For comparison reasons the set also contains manually set eye postions.
http://www.humanscan.de/support/downloads/facedb.php