Pix Remix [App Store, US$2.99] was previewed for TUAW at WWDC '09, and you can watch Victor's video of the app in action.
Creating these animated shows is simple and intuitive. You pick a show type (collage, slideshow, or pan & zoom), select some photos from a photo library or camera roll, and then drag, pinch, and tap to arrange the photos or determine the start and end points of the pan & zoom. Don't like how your photos are arranged? Just shake your iPhone to let the app do the job. You can add titles to every slide, and when you're ready to share your work, you just tap the send button.
However you choose to send your show, the recipient gets a link that takes them to the Pix Remix website to view it. If another Pix Remix users sends you a show, you can view it from within the app.
The developers at Jump Associates have done a wonderful job of making this app bug-free. It's one of the cleanest version 1.0 apps I've used in a long time, and considering all of the iPhone technologies and external links it takes advantage of, that's saying a lot.
Why just send a postcard to your friends to make them jealous of your vacation when you can send them a Pix Remix show instead? Check out some screenshots below and check out a demo slideshow here.