Color Expert helps artists and designers identify, translate, capture and show color using their iPhone or iPod touch. You can use an interactive color wheel to identify a target color and then find several palettes backed by color theory. When you're satisfied with the palette you have created, you can e-mail it to yourself or someone else for future reference.
I've been working with a very fussy client on a website. We just couldn't come to an agreement on the colors. She loves green, Today, I was in her office and she pointed to her sweater and said that was the color she wanted.
I pulled out the iPhone and opened Color Expert. I took a picture of her sweater, selected the green I thought she would like and showed her the analogous colors based on that selection and she was excited as those were the colors she wanted. -DreamweaverMM (source)
I can definitely see how that would be useful. Do you rely on technology when you are creating or designing something, or do you prefer to use more traditional media?