I read something recently (perhaps on TUAW, but I'm not sure) about how you could use the iPhone's camera with a magnifying glass to get reasonable-quality close-up images. This might be pretty obvious to shutterbugs, but I thought it was cool. I decided to try it out with my loupe and a book cover and see how it worked. I was impressed that you can clearly see the halftone screen rosettes.
This is a very rough and quick demo. Click the thumbnails for full size.
Without loupe, and with loupe:
This is a very rough and quick demo. Click the thumbnails for full size.
Without loupe, and with loupe: