I just recently bought an iPhone 3GS and have been browsing through the various apps. Hereīs one that might be of interest here. Itīs called Peppermint. Iīm not selling it and probably wonīt buy it. It just seemed interesting as an application. The blurb says:
Powerful color wheel with flexible adjustments.
Easy access for HSV, RGB, CMYK, LAB and hex values
For a full review and some screenshots: