If you always wanted a 'magic wall' for your iPad, Photoboard HD (US$2.99) is probably as close as your are going to get. This app originally appeared on the iPhone and iPod touch and lets you manipulate photos by scaling and rotating them to create interesting collages.
The new iPad version has higher resolution (natch) and photos look pretty stunning on it. Obviously inspired by the breakthrough work of Jeff Han, and widely seen on CNN, Photoboard HD is fun to play with, but I'm searching hard for a practical use. Certainly you can re-arrange photos and make for some interesting groupings, but beyond that you're pretty much done.
It would be nice to see more options for framing the pictures, and more backgrounds, including ones I choose myself. As it is, the app is a nice demo of the graphic power of the iPad, but most photographers would probably rather create their collages in Photoshop.
I liked the idea of this app, but it needs more customizable features, and a definite purpose.
There are some screen shots in the gallery below, but at a reduced size the screen shots don't do justice to the quality of the images: