O.P.I Cost: Free For folks heading to get a manicure, O.P.I., the ubiquitous maker of nail polish, offers an iPhone app that helps them select from 200 colors, which feature wacky names like "Blushingham Palace," "Lunch at the Dehli" and "Melon of Troy." Users can search for a color by shade or name -- useful if you can only recall part of a hard-to-remember name ("I'm Not Really a Waitress"). The app also shows what the polish will look like on a hand; users can adjust the shade of the skin to match their own coloring. In addition, the app lets users "tag" favorite colors so they can quickly access the names when they're in the salon. We wish the app had more features. A few of our ideas: information about pricing, news about current nail trends, a step-by-step guide about how to give yourself a manicure, the closest locations to buy O.P.I polish and a nearby nail salon locator.