#0 - March 5, 2007, 11:43 p.m.
I have WoW installed, via the trial download (which lacks the BC expansion in it).
Using the link provided when trying to log in, http://www.worldofwarcraft.com/burningcrusade/download/
"We will be offering a direct download of the Burning Crusade expansion at a future date in time. Please keep an eye on the main website for more details."