Through entries on the blogs of Marc Orchant and Web Worker Daily I found a new web application that's geared to support the Getting Things Done organization approach: Nozbe

From what I read, Nozbe seems to be inspired by Backpack, but made strictly to implement the GTD concept of next actions, contexts and projects. I currently use Backpack to organize my tasks, but I have to implement contexts and projects by putting them on different pages which sometimes makes shifting things around a bit complicated. I've tried other online GTD solutions, but Nozbe seems to be the most appealing to me at the moment, because it combines the simplicity of Backpack with the complete GTD concept and nomenclature.

Marc is excited, too:

So when I saw Nozbe, I smiled. Here's an application that gets the essence of David Allen's approach exactly right in the browser where I can conceivably touch my projects and next actions from any of the devices I use in any of the locations in which I work. It's a matter of a few clicks to define a new Project, add a few actions, assign a context and estimate to the action, and capture some related notes.

Judi Sohn from WWD points out that there's still a bit of work to do, but finds it an interesting solution, too:

Nozbe still needs work. In addition to the uneditable contexts and the limit on projects, it doesnt work with any other on or offline system. No importing/exporting tasks or projects to work with a favorite calendar or email application. No RSS feeds. No reporting. No date-specific tasks. Sometimes you have to do something because its due, regardless of the accessibility of the context. I think all of these things can be added without losing the simplicity that makes this application stand out.
Its a good start. If youre a GTD fan, this is a web application to watch.

I'll give Nozbe a try over the next days.

Update (2006-02-12): Today, Judi reviewed Vitalist and gives it a thumbs-up in comparison to Nozbe:

If stuck on a desert island and forced to use one online GTD application, Id be bookmarking Vitalist. Nozbe is more straight-forward, but I appreciate Vitalists reminder, date and XML/feed features.