If you shoot with a smartphone, you probably find its built-in camera adequate for capturing and sharing pictures but limited as an image-manipulation and editing tool. For just a few bucks, you can greatly enhance your phone-cam with one of thousands of photo apps. Here are some cool ones, for Android and iPhone devices.

Adobe Photoshop Express 2.0
Apple App Store: $4
With the Camera Pack upgrade of this powerful editing app, you get noise reduction (to remove grain), a self-timer, and auto-review for quick deletion. Even with the free version, you get basic Photoshop in the palm of your hand.