A Pragmatic Guide to Getting Things Done
GTD is a great system; once you follow it (in some form), it quickly becomes difficult to imagine how anyone lives their life without it.I have found Evernote to be a great tool to implement a GTD system.  Evernote's greatest strength is its flexibility.  It works on basically every platform and integrates with most other tools you use.  It doesn't really tell you how to use it though, which is where GTD fits in perfectly.  (And it turns out to be really helpful to integrate as much of your system as possible into one tool.)I found this site to be a great resource getting started with GTD and Evernote: http://www.thesecretweapon.org/My current system is very similar to what they describe, although I added a 'Waiting' status, which includes both things that need to be done at or after a given time, and things where I want to remember that I'm waiting on something outside my control (a reply to an email, for instance).  I set reminders on everything in there.The one other significant tweak I made is to use notebooks instead of tags for the 'when' portion.  Since every task needs to have a 'when', and since every note has one and only one notebook, this seemed like a logical fit.  So instead of the 'Current' notebook they recommend, I simply use a Current stack containing a notebook for each priority level.I also use Powerbot to improve clipping emails from gmail.Anyway, the details don't matter and are easy to change.  The main point is, give GTD on Evernote a try, and you'll be glad you did.