PS Express - *
Cost - Free

Adobe Photo Shop Express is a really great photo editing app for both the iPhone and iPad. I downloaded this when I got my iPad, and I have to say I like it much more for the iPad than the iPhone, just due to the screen size.

When you launch the app, you have the option to share pictures or edit them. I don't tend to like sharing from apps, so I usually just edit pictures. And since most of these screen shots are self-explanatory, I'll leave you to understand how to work the app. Obviously you can do more advanced things if you are aware of the PROPER way to photo edit, and I don't mean using Picnik.

I also didn't apply any effects to the image, because I just forgot. And I'm about to go to a graduation party so I don't have much time. (I took that picture in Europe.)