How to get 4 megapixel iPhone photos
ms2005 on HUKD posted about a new app available through Cydia (must have a jailbroken iPhone) that claims to create 4mp iPhone pics.
The app works by taking 6 photos in rapid succession and then knitting them together to make a higher resolution pic. Once you've snapped the pic, the app puts the six photos into a queue. In the queue you hit the "align" button which automatically lines up the photos and then you hit the "enhance" button which automatically enhances them. Once you've done this you can save the enhanced photo to your normal camera roll.
We tried out the app here and although it works as claimed the photo quality of the final enhanced photo was not greatly different from the equivalent photo taken with the normal iPhone camera app. There was a small difference on the readability of small text so if you are taking shots of magazine article/newspaper clips this may help (especially if you do so on a train). JamesMQ and iainmann also backed this up in @bitterwallet tweets with comments about instability and only small increases in legibility.
The app is free to use unless you want additional features (a quick shot feature that takes 6 pics in 2.5 seconds and then automatically choses the best one and the ability to have more than one pic in the editing queue).