CameraBag (U.S. $2.99) is a popular little utility that has had life on both the Mac and PC platforms, as well as the iPhone. Now it's made it onto the iPad, where it will be welcomed by photographers.
CameraBag is a photographic cropping, framing, and filter tool. The app comes with some preset filters like "Helga," which gives you a square format image with washed out highlights and some vignetting. "1962" provides dynamic black and white images, and "Magazine" delivers saturated tones to your photos. There are other presets as well, plus a button that generates a random variation of an existing preset. If you don't like what you see, you just keep hitting the button until you get something you like.
What are the downsides of CameraBag? Well, there's no control of the cropping, so you can't move the object in the frame. The frames are pretty basic, and there's no choice for the color of the frames. Basically, you get white, except for the cinema frame that consists of black bars.
CameraBag preserves the resolution of your originals, and it's possible to scale them down if you'd rather have a smaller size for posting or sending photos via mail.
Finished images are saved back to the iPad library or can be emailed. Some people will say that without a built-in iPad camera, there's no reason to even bother with photo apps on the platform. That viewpoint is short-sighted. Through a USB connection, you can import photos from iPhoto. With the pending iPad camera kit, you'll be able to pull in photo files (even RAW format) from your digital camera, and then modify the images at your pleasure. This app and Photogene, which I reviewed a few days ago, aren't really Photoshop on the iPad, but they do go a long way toward providing a way to edit your photos for either improvement or fun.
Be sure to visit the CameraBag website for more examples of what the app can do.
Here are a few of my own samples: