How hard can it be to add a "rotate" action? Can you guys teach me how to rotate an image so that when sent by email we actually send it in the right rotation?
Edit: As of 2016 this functionality is now part of iOS's native photo app

The following information pertains an iPhone, but I assume the iPad is identical in terms of features.

Short Answer: You can’t rotate photos in the default iOS’s Camera Software; you need to install a third party utility, like PS Express (recommended and free):