There are quite a few apps that can create painterly effects from photos. Painteresque is very simple (no options for the iOS version at least) but can create lovely results.
All you need to do is take a picture or select one from the Photo Library and let Painteresque do it's thing. Then save the result to the Camera Roll.
This image called for a painterly rendering:
Painteresque also works fine from B&W:
Combine Painteresque with Image Blender and you have a lot more options.
We love Painteresque and can really recommend it.