A Flickr user,
Daniel Forsythe, has documented a hack to turn the iPhone into a Macro camera.
Usually the focus is set to infinity at the factory (the small sensor size takes care of depth-of-field) but you can change it to a close-focussing macro lens. Which makes it more useful for close shots (barcodes etc).
We have already discussed
reading barcodes using your cellphone, you can use this hack to optimize the iPhone for barcode reading.
Instructions:
http://www.flickr.com/photos/defor/sets/72157606981066775/
