There are a lot of apps for creating panoramas with your favorite camera equipped iOS device, and most do the job well. There are paid apps, and others like the free Photosynth from Microsoft which stitch lots of photos together vertically, horizontally, or in a complete 360 degree views.
If you do a lot of landscapes, take a look at the US $0.99 Panorama™. It's dead easy and guides you with onscreen prompts about how to move your camera. When you are done, you can apply built-in filters, like Rice Paper, Vintage, Old Photo, Sketch and more. With another click, your photo is on the way to friends or family via Facebook, Twitter, Flickr, Tumblr, and of course, email.
The app worked fine and controls were obvious. You can see the images coming together in real time, and applying filters is a fast process. They can be selected in advance and viewed before you ever snap a photo. My only complaint is the app maintains its own library, and it takes an extra step to get images to your camera roll. That should be a direct save, not a second task. You can only take horizontal photos. The app prevents vertical (portrait mode) image capture.
The output is seamless, and while I'm not much for adding filters to photos there is a large selection available. When you send an image, Panorama™ provides the thoughtful touch of letting you add a note. Photos are time-stamped and geotagged.
Panorama™ does what it advertises. iOS photographers will also want to consider Photosynth (free), AutoStitch Panorama ($1.99), 360 Panorama ($0.99), and Panoramatic ($0.99). I've used all these apps and they do a good job, but differ somewhat in workflow and features.
If you have a favorite, let us know in the comments. Same screenshots from Panorama™ are in the gallery below. Note that the samples are not at full resolution, and not as wide angle as the app allows.
Panorama™ requires iOS 4.2 or greater, and works on any iPhone from the 3GS up, the 3rd and 4th generation iPod touch, and all iPads with a camera.