I had a brain wave a few days ago, and wondered what sort of facial recognition software might be available for genealogy.
A quick survey of the web didn't reveal anything right away that was specifically dedicated to genealogy, but a couple of options presented themselves. The first was to use Google's Picasa Web albums. Upload your photos, ensure that name tagging is enabled, and away you go. After a few pictures are identified it will start to make suggestions based on previous name tags you have assigned.
The other possible option is Facebook, which automatically tags people in pictures, and there is no reason not to use that ability for figuring out who is who in old picture. Once again, all you need to do is tag the first few occurences of a persoon, and after that Facebook starts doing it for you for any other occurrences of that person.
Finally, there is also an Apple application, iPhoto, that has facial recognition built in.
Personally, I think I like the Picasa Web Albums better. It is in the cloud making it easier to share, it can be synced to your own computer, and because the pictures are web based, they are platform independent. Just make sure that you send the link of the album with the pictures to your cousins and contacts who might be able to help.