The new Photoshop Elements is out, and one of the new features is face matching.
I try to tag my photos with who is in them, so this is a great feature for me. Whenever I import a batch of pictures, it offers a window with closeups of the faces of all the people in the pictures, and I can control-click on all of the pictures of a certain person and then tag them with their name. This is great when I later want to find all the pictures of a particular person.
Looks like the face matching algorithm is pretty loose – look at this face it found: