iPhone UILabel text soft shadow

Question

I know soft shadows are not supported by the UILabel out of the box, on the iPhone. So what would be the best way to implement my own one?

EDIT:

Answer 1

Additionally to IIDan's answer: For some purposes it is necessary to set

label.layer.shouldRasterize = YES

I think this is due to the blend mode that is used to render the shadow. For example I had a dark background and white text on it and wanted to "highlight" the text using a black shadowy glow. It wasn't working until I set this property.