I've been meaning for months to post about an awesome new feature in Google's Picasa photo-management software:
Given a set of photos of a person, the Face Movie feature creates a slideshow-like movie that rotates and shifts each new photo so that the person's face stays more or less still in the middle.
It's an amazing effect. Prose descriptions of this don't do it justice; instead, watch the demo movie:
(If you don't see a movie here, follow the link to the YouTube page.)
It's like magic. I haven't had a chance to try it out myself—I usually use iPhoto instead of Picasa—and I see from some other people's Face Movies on YouTube that the results aren't always perfect. But they're often really cool. Check it out!
In case you don't have Picasa: it's a downloadable desktop application (not to be confused with the related online gallery site Picasa Web Albums), free for Windows and Mac. And I believe that when you run it, it searches your disk for photos, so I think you can use it in conjunction with iPhoto. I'd be very hesitant about editing photos in both applications—I suspect iPhoto would be unhappy about that—but I'm guessing that creating a Face Movie wouldn't interfere with iPhoto. I'll try and remember to try it sometime soon.