While at Adobe Troy Gaul implemented the Lightroom & ImageReady color pickers, including supports for choosing Web-safe colors (a godsend to me when it arrived).  Now that he’s an independent developer, he’s released InfColorPicker, an open-source color picker for iOS.

By the way, if you use Instagram & have an iPad, you should get Troy’s Instagallery app; lots of nice attention to detail.