Facebook Design
With facebook recently reaching 1 BILLION users, it is a platform that businesses cannot ignore, no doubt facebook will continue to evolve, but as from 2012/2013 the ability to edit it is still fairly ridged.
The key is to match the style and visual language of facebook, and control the areas in which you can have influence over the design, below you will see some screen shots of a facebook page I created for Tesco Pet Club