Applying fondant to a square cake is not different than applying it to a round cake. Just do the corners first.
I don't apply a full layer of BC as I find it can make the fondant lumpy appearing if the BC shifts at all. I apply a thinner layer that is a little thicker than a crumb coat..
its really not hard to put fondant on a square cake. just move your hands downward instead of side to side, and focus on keeping your corners smooth. i like to keep my bc a little thick under fondant, but still not as thick as i would if it was a bc cake. does that make sense?
if you go to this link there are tutorials on applying fondant, one of them is about applying to a square cake 
http://www.atecousa.net/learn/satin_ice_1.shtml
Quote by @%username% on %date%
%body%