The easiest way to use these is to add a UIButton instance to your view in Interface Builder, then change the underlying class from UIButton to GradientButton. Because there's no way to create IB palettes for iPhone classes, you'll also have to implement viewDidLoad and set the gradient or use the existing methods there.
I posted to delicious.com
iPhone Development: Improved Gradient Buttons
http://iphonedevelopment.blogspot.com/2010/05/improved-gradient-buttons.html