http://www.nytimes.com/2010/07/13/science/13gravity.html?...
A string theorist is not tethered to the notion of gravity, saying the force is a consequence of thermodynamics.
This video uses line drawings and simple diagrams to give you an idea of what it would be like to exist in some of the higher dimensions. As you might expect, it starts getting pretty trippy once it gets past the third one.