Dutch software developer Johannes Verelst has written up his system for Getting Things Done (Dave Allen’s task management philosophy) with Mail.app and iCal.

(If you are mystified about endless references to “Getting Things Done” (or GTD), Merlin Mann’s 43 Folders is still the best way to lift the fog. See his recent “Getting Things Done: Recap for ‘07″ post for a list of red-hot how-tos and tutorials on boiling GTD down to something workable for you, or jump right into his “Getting started with GTD.” )

Johannes’ way of using Mail.app to get things done is not like my own Mail.app GTD system which makes it all the more interesting and useful to read. There is always something to learn from people who do things differently.

I make an effort to keep everything in Mail, which then acts as my “Bucket”, processing hub and also my to-do list. Less swapping from app to app helps me to focus on getting the tasks done.

Johannes likes to dump stuff out to iCal. He uses calendars to separate out his projects and contexts. A clever combination of Mail Act-on, Quicksilver and applescript helps him to create an all-encompassing system.

I use MailTags to set iCal to-dos, but only so iCal’s alarm will shoot a reminder back into my inbox about something that needs to get done. MailTags’ keywords for @Action, @Waiting and @Defer and its project tags give me enough power and control to manage a confusion of Real Life, blogging, freelancing and family tasks efficiently.

While Mail remains for me what Johannes calls a “Cockpit”, he uses DoBeDo as his cockpit, managing his to-dos through the widget’s interface.

His GTD toolbox list at the end of the post shows that his system is up and running for less than USD 70 (and most of that is for the software to sync his Palm T|X). It pays for itself in a week at the outside.