Is there any software that will do face recognition in photos?

Digikam
(...will in the next release, very soon. there may be a beta/development version that does now. please read:)

"Aditya Bhatt added face detection and recognition to digiKam. He says: 'Because of my project, digiKam can now automatically detect faces in photographs. It allows you to tag these faces with People Tags, and can also identify unknown faces and automatically tag them. My work also introduced a wrapper library called libkface that can be used by other KDE apps. Right now everything works okay, but it needs a bit of usability and GUI work, as well as some tweaks to libkface. Hopefully my work will make it in time for the Christmas release, which will be 2.0!'"

this is taken from the latest google summer of code update on kde.org, here: http://dot.kde.org/2010/12/14/kdegoogle-summer-code-2010-part-1-2

Google photos, the successor to Picasa may satisfy your demand. You just drag and drop the pictures folder to google photos (website - but it's actually native code via Chrome's Native Client) which automatically organizes them - you can go to Albums -> People to see all them categorized by recognized faces.

OpenCv(Open Source Computer Vision) also has the Linux versions.It is a library of programming functions for real time computer vision.Many software about recognition of photos also use opencv.Opencv can also solve your problem definitely.

The face recognition result: