I've written a plugin for my Windows Mobile smartphone to better suit my GTD needs - to make it easier to triage the emails in my inbox in one pass, moving them to my task list, diary, or project materials as appropriate.
In desktop Outlook, if I get an email from someone asking me to do something, I can move the information to my Tasks list by dragging the email to my tasks folder. I get a new task item, with all of the information in the email copied across. Similarly, emails about events can be turned into Appointment items by dragging to my calendar folder and so on. This way, I'm not storing actions in my inbox.
What I've tried to do is write something that provides the same ability in Outlook Mobile.
If anyone thinks this would be useful to them, they are welcome to a copy: