Patrick Rhone has written a great post on his GTD setup in Backpack. Backpack is a simple todo online system with ability of attaching notes, files, and images. With his detail description on his setup, you can have a very effective GTD system online so that you can access it everywhere with Internet access:
Several days ago I had a revelation about my current use of Backpack as a GTD tool and how I might use it even more effectively. Part of this revelation was spurred by an e-mail I received from Swedish reader Daniel Westergren who had some questions about my use of Backpack for GTD after reading my Productivity Whitepaper. The subsequent e-mail exchange that followed led me to some serious “getting real” about my system.
I have described my system in great detail before so I wont go into any more here. Basically, up until now, I have been using the front page in my Backpack as a “Today” page – i.e. things I would like to get done today. I have been moving by copy and paste next actions from my @Action, @Projects, various individual project pages and @Errands pages to the front page. In other words, my own laborious “kinkless” system of next actions. One benefit to this was the very act of doing this forced a daily review of the items and projects. The obvious problem was how time consuming and counter efficient all of the shuffling around is. Basically, I was using the front page for all of my next actions and therefore would end up with duplicates as keeping track of it all was a tangled mess…
Backpack: New GTD Implementation Ideas – [patrickrhone.com]