FYI - David Allen Co. offers a free trial to the Connect subscription service.
I swear I'm not getting paid for this (What? David, you want to give me a $20 bill to do what?) but if you try it I would highly recommend going through the Getting Started section which has a collection of audio and video by David and members of his team that walk through each aspect of setting up a GTD system.
Thanks, Mark, for your post! If you'd like to learn more about the GTD Connect free trial, or sign up for it, you may do so here.