Find the more advanced project at RSully/RSColorPicker. This project (ANColorPicker) uses images and requires a specific size for the color picker views, whereas RSColorPicker is dynamic in both size and generation.
"Use this simple color picker to get colors that a user picks. The color picker must be a certain size, and requires several images files in the bundles package contents. The picker is very easy to use with code and to the user. Enjoy :)!"
Very basic example:
ANColorPickerViewController *colorPick = [[ANColorPickerViewController alloc] init];
UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:colorPick];
[self.window addSubview:nav.view];
Actual example: See ANColorPickerViewController.m (-viewDidLoad)