Windows/Mac: Google's free desktop photo organiser is stepping up to iPhoto and other web tools by adding face recognition and syncing it with Picasa Web Albums, making it easy to send Uncle Bob every single photo you've got of Aunt Marla.
The new Picasa 3.5 contains a facial recognition feature similar to the one already present on Picasa Web Albums, but letting it run over your likely vast collection of assorted photos stashed on your hard drive is a lot more convenient. Picasa creates a new sidebar menu list of "People", and asks you to name the folks it finds in its main "Scanning" menu. If you're signed into Web Albums with a Google account stuffed with contacts, that's pretty easily, actually — just start typing a name, then select the contact that pops up as you type.
You'll probably have to leave Picasa running a long time to get through everything—after 20 minutes, it's about 9% through with 13.8GB of photos on my laptop. As you might guess, some of the facial matching is hit and miss, but you get to approve any of the picks Picasa isn't absolutely sure of, and if someone's in your photo library who you don't want to take the time to tag, you can send them to the "Ignored People" pile. All this is in service of a better search function, so you can more easily find photos of yourself and your spouse, your spouse and her friend, or any combination of people, dates or other search parameters.
The other big addition to Picasa 3.5 is a tool to use integrated Google Maps pickers to geo-tag photos without having to have Google Earth installed and used as a marker generator.
Read up on Picasa's name tag features, and grab a copy of the free download below. Tell us how well facial recognition is working, or not, with your own photos in the comments.