Welcome Mike. I used to be so disorganized it was embarrassing. My office was a disaster - just tilted piles of paper and assorted crap. My email was a single inbox with hundreds maybe even thousands of emails. I would miss deadlines and forget to do things and lose important documents.
GTD has turned me into an organized person, which I very honestly did not think was possible. Good luck - definitely read GTD from cover to cover and remember that it is a practice not an either/or proposition. At least in my case I am always getting slightly disorganized and then resetting and refocusing. This is why the weekly review is so vital. Once you've been at GTD for a year or so I recommend reading "Making It All Work" (David Allen's third book after GTD and "Ready for Anything"). I hate to sound like a proselytizing fanatic, that book was a real eye-opener to the true possiblities of GTD.