Those with an artistic bent have been making color-isolated photos in Photoshop for years, but a recent crop of quick and easy tools for doing just that has allowed novices (like me) to create some of the same beautiful photos in a fraction of the time.
ColorWash, currently US$0.99 in the Mac App Store, is one such program. It allows you to make color-isolated photos in minutes. You load your image of choice into the app, which will then remove all color from it, giving you a grayscale photo canvas. You then 'paint' the color back in using a brush tool, restoring the original colors into the areas of the photo