I am also an attorney looking for advice on how to integrate GTD into my practice. My firm (25 attorneys) uses Time Matters for calendering and task management. I have slightly broken away and have setup my Outlook using David Allen's Outlook Guide (projects = Task Categories) but I am struggling with the ability to create multiple action items within a single project. I'm also looking for a way to take my tasks with me on my iPhone, and have experimented with Toodledo, but did not really like it. I am thinking of potentially making the switch to Nozbe or another 3rd party app and abandoning Outlook as my GTD action item manager. Thoughts?