http://www.midatlanticcakeshow.com/images/2007/wcc/2007-3-rink-becky.jpg

Here is a cake that I found due to another CC member (she was looking at the very cool tea-pouring cake). What is supporting the tilting layers? Is it shaped styrofoam? Any pointers would be appreciated!

My guess is it is styrofoam with wooden dowlings.

Do you have to "insulate" the styrofoam from the cakes above and below it with cake boards, or just cover them in fondant? Has anyone made one of these cakes before? Any other tips my friends? Thank You!

Yep, I'd definately agree it is styro wedges.
If the styro is covered *completely* w/fondant no need for any other covering. OR you could cover it w/press & seal (plastic wrap), the put a wrap of fondant around the sides.