The purpose of this application is quite straight forward. You choose a color and the application will generate a set of complimentary colour schemes: monochromatic, complimentary, analogous, or triad, for you.
This application's features are not unlike many of the web based colour scheme generators, like ColorSchemeDesigner.com. Web site like Colr.org will accept a photo from Flickr or uploaded from the user's computer, to generate a complimentary colour scheme from it.
I would not call myself a designer, but I do appreciate design, and I do often build web sites. For this application to be useful to me, I would need the ability to manually enters the HEX (preferred) or RGB codes for the desire colour then have the application generate the colour scheme.
This iPhone application is available on iTunes for USD1.99; 1 dollar less than the OS X version, I think they are both too much to ask for when ColorSchemeDeisgner can do the same thing for free.