Color Splash costs € 0.79 in AppStore. 50% cheaper than otherwise may turn Colorsplash any photo to grayscale images that can be selected areas, however, continue to color and works perfectly in most cases. A nice little gimmick.
Color Splash is nice app, as opposed to the Best Camera, CameraBag, but quickly makes no fun anymore. There have been deleted in favor of other photo editing programs.
Even great thing you can do right now in this direction on the iPhone. For many small things we need no longer to download photos to your Mac/Pc! You can zoom in so, so you can get out pretty good results.
The images will be recalculated with 640×480. For an iPhone 3G should watch on the iPhone quite nicely - but sync with Mac/PC and watch on big screen or print out the pictures!