If you are using Corona (or any other software that uses sprite sheets for animations), you need to create sprite sheet files (basically a file with all poses of your animations). There are several sprite sheet software available, although most of them are paid. In order to avoid pay premium for basically just one feature, I decided to create a Photoshop Sprite Sheet Exporter. Check how it works and download it at http://asouza.com/blog/?p=119

Enjoy!