That's when you start with two pieces of wood, side by side, a few inches apart, then on top of that, you put two more pieces, side by side, a few inches apart, in the other direction... like a log cabin... and keep going from there.
It's not really something you'd really do for firewood, I was just making an attempt at humor, but I have seen it stacked that way when the wood's going to be used for a kiln, forge, or still <img src="/images/graemlins/wink.gif" alt="" />
Seriously, this is a way to quick-cure green wood, but average Joe won't go to that much work, unless he needs the wood to put out some really serious heat, and if the wood's that dry, it gets kind of hard to bank a fire for the night.

Troy