KGTD for OmniOutliner
A GTD application for mac users has been released.
‘Essentially, KGTD is a single OmniOutliner document with some fiddly bits (ok, we can call them “buttons” if you are going to get all technical) that allow you to manage two views of your GTD tasks: projects and actions. You can archive completed projects to get them out of the way, and it should all look lovely in whatever colors and fonts you choose.’
Read more about this free application add-on here