I just stumbled onto the thing that is going to finally let me fix the mess that is my craft closet - The Give Back Program.
Basically, you go to the Give Back Box site, print out a shipping label, slap that onto a box, and voila! Just put it in the mail and you're good to go! There is also the option to have USPS come to your house and pick up your boxes, which means you can get rid of a lot of stuff at once. (Which I plan to do once I gather together enough supplies for a weekend purge.) This seems ideal either for folks with no time, or folks with no transportation.
Give Back Box recommends reusing old boxes from shipments you've received, so there's a recycling component to it. Best of all, the only weight limit is USPS' maximum (which happens to be 70 lbs.). The only downside is: No electronics. (but there are plenty of other services that will collect those for you. Or you can flex your maker skills and reuse them for parts!)
For me, personally, just getting rid of old stuff has been the biggest hurdle to my getting organized. I've made plenty of attempts, but my plans fail from the start without the ability to send stuff off to where it can be useful. I've printed off several labels now, and am about to hunt down cardboard boxes and tape.
Later on, I hope to post about my experiences with mind-mapping, and using that to plan an organization system before I go moving things around again. I'm hoping to share that info in a few weeks.