http://jeremykun.com/2011/07/27/eigenfaces/
http://nbviewer.ipython.org/github/rcquan/sklearn-practice/b...
The wikipedia article (https://en.wikipedia.org/wiki/Eigenface) also contains code for a MATLAB implementation.
Nonetheless, I've found it to be an interesting concept. There is indeed a homework from the Coursera ML course for computing and visualizing eigenfaces, and the course (and the Stanford CS229 notes) discuss PCA further. I decided to explore the ideas further and distill it into a blog post specifically on eigenfaces.
Goal is for it to serve as a condensed tutorial on an interesting topic! I definitely learned a bunch writing it, and it may be interesting to others who have yet to come across to concept.