The startup has released a free iPad application that lets you collage your pins, as well as those of other users on the network. It's easy to find, add, resize, rotate and otherwise assemble your collage. You can also add borders to images or select "crop" to remove white space.
The app isn't perfect: If you have a board with more than 25 pins, you won't be able to load them all. (Gili Golander, Bazaart's fashion director, tells me this is a result of Pinterest's RSS feed limitation, and there's nothing they can do about it.) The crop button tends to completely erase light-colored images. An "undo" button would be a welcome addition as well. But it's a nice start.
Beyond collaging, the Bazaart app is also a decent Pinterest client: You can explore other boards, repin items and pull up their source pages -- meaning that all of the products pins are also shoppable within the app.