There are many Photo editing App's available at the Apple IPhone Store one the good ones is Fotegrafix - Popcam Camera. This App gives you the flexibility to add filters to your favourite pictures just like a cool sticker...
This App is free and available on IPhone Apps. They have recently launched two new filters for Valentine's day and Chinese New Year.
Some of the pictures that I edited with the help of this App are below. It is cool and very easy to use!!
Download this App today and make your own memories!! I give this App 5 Stars :)