The easiest way to learn this is on a flat area with front foot strapped in and back out.
1) Place back foot against back binding from the center of the board.
2) Place weight on back foot like doing a wheelie.
3) When the front of the board lifts up pop up and forward to lift back end off ground.
4) stay centered land then try again until you got it.
5) strap in and take it to the slopes
PS video of all this and lots more coming this winter of 2008