Flatland by Edwin A. Abbott is a good book that tries to describe exactly what it would be like for a 2d creature to be visited by a 3d creature and his understand of the third dimension.
http://www.alcyone.com/max/lit/flatland/ is an online version of the book. Then there is Sphereland which was written afterwards I cant remember exactly what that one was about but im pretty sure its the same sphere visting flatland with more information.
-Marc