Sounds great, but it is really innovative? Can you really use it to match colors precisely?
On the innovation front Sherwin Williams released a similar app back in May called ColorSnap. It works similarly to myPantone but matches photos to the Sherwin Williams' library of paint colors. Since ColorSnap is free (and Sherwin Williams' paint more readily available) it's the better option for the casual shopper interested in matching paints to other items.
Neenah Paper, Inc. also released a free color app in May called Think Ink: Color Unleashed. It allows the user to create color palettes based on photos, personality traits, Neenah paper stock, or RGB values. Personality traits? Well, o.k.
From a technical standpoint iPhone color apps will give you a close approximation, not perfection. Screen resolution limitations exist, even with the lastest iPhone 3G release. The iPhone's resolution, measured at 163 ppi (pixels per inch), is deep enough to register a decent color measurement. However, color matching cannot realistically approximate variables such as light and reflection found in printed colors, paint colors, or paper color in the real world.
For fun, try Pantone's other iPhone app, a freebie called Colorstrology. Developed in partnership with psychic Michele Bernhardt, the Colorstrology app works similarly to a horoscope. It will direct you to your favorite color as well as give you a fortune-cookie thumbnail of positive character traits.