PowerSketch is a US$0.99 app from the developers of PowerCam that takes any image and applies a variety of filters to turn the image into what looks like comic book art or a pencil drawing, and add effects like rice paper, neon and more. The app supports live preview and can operate your iPhone camera, or you can pull something from your camera roll.
Finished photos can be sent via email, Facebook or Instagram directly from the app. I found the app does what it advertises, and there are plenty of choices. You can even create collages. Like all filter-type apps, you can overdo it, but this would be a nice app to take a holiday photo and turn it into art for a card to send to friends and families. It also has some nice effects on portraits, but some, of course, can be pretty grotesque. This is the kind of thing you can do in Photoshop or other image editing programs, but it's nice to bring this to the iPhone. While other photo filter apps can do similar effects, this is one dedicated to doing these high contrast pencil and other type renderings to your photos.
The app is easy to use, and there is built-in help and a welcome screen with instructions.
One downside, and I see this all too often, is that this is an iPhone and iPod touch app. It is not universal, and while it ran on my iPad, I had to scale it up 2X. I think the larger screen lends itself to photo editing, and it is a mystery why so many apps aren't universal.
Still, Powersketch is a nice addition to your arsenal of photo editing tools, and certainly worth the $0.99 price. The app requires iOS 4.3 or later and supports iOS 6 and the iPhone 5 and latest iPod touch.