Here is a simple way to achieve the simple gray rounded rectangle of yester years. Courtesy of tech tutorials and their great little YouTube tutorial
In the Identity Inspector add the 2 new Runtime attributes.
Set background color & text in the Attributes Inspector.
Here's another good tutorial; http://ios-blog.co.uk/tutorials/user-defined-runtime-attributes/
Now for some geeky details;
These attributes (properties) are properties of CALayer