Purchase a list of LEGO parts If I have a list of LEGO parts (exported from LEGO Digital Designer or Bricksmith) is there an easy way to purchase all of the parts either on LEGO's Pick a Brick or on Bricklink?

I know that I can go through the list one by one and order the pieces but I was hoping that there might be some tool where I can upload a list and have all of the parts automatically added to my cart.
Doing this for Pick-a-brick (which sports an antiquated UI) requires some fairly advanced hacking. See this question. It's unfortunate that there is no simple interface for importing composite sets of bricks.