With iOS 5, Apple has moved the powerful CoreImage framework from OS X over to their mobile operating system, allowing the Photos app for iPhone, iPod touch, and iPad to do some basic image editing work. Now, by tapping on the edit button at the top right, you get access to several iPhoto-like tools:
As is the case with most built-in functions, it provides the basic set of tools but is by no means a feature complete photo editing app. Still, it's free, its bundled, and very many it will be good enough.
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