Color picker plugin for Interface Builder
There's a nice color picker from Panic which works well with IB: http://panic.com/~wade/picker/
Xcode plugin
This one gives you a GUI for choosing colors: http://www.youtube.com/watch?v=eblRfDQM0Go
Objective-C
UIColor *color = [UIColor colorWithRed:(160/255.0) green:(97/255.0) blue:(5/255.0) alpha:1.0];
Swift
let color = UIColor(red: 160/255, green: 97/255, blue: 5/255, alpha: 1.0)
Pods and libraries
There's a nice pod named MPColorTools
: https://github.com/marzapower/MPColorTools