Freecycle is essentially a bunch of groups around the world, that seek to help each other out by giving (and getting) stuff for free in their individual towns.
It's free to join, and once you have joined you simply locate a group near you and start participating. Most groups are in the USA, UK , Germany, France, Canada and Australia, but they are keen to make this a worldwide phenomenon, so if there is no group in your area, then you are free to start you own!
As the name implies, Freecycle is designed to be a sort of non-profit recycler, the idea being that if you don't want something, someone else might. What sort of things get exchanged? All sorts, from pianos to old mobile phones to chairs and sofas. If you are clearing out your house, this is a good way to get rid of stuff (as well as being community friendly). And if you are a bit skint, this is a good way to find things you need for free (the ultimate money saving device).