I hadn't heard of this, but now I've just read up on it a little and it's really interesting. I'm definitely an environmentalist, and this seems like as good of an approach to dealing with plastic as any right now.
What do you do with the completed bottles? Is there somewhere to send them or do folks all just make stuff with them? I'm not that crafty.
If you google local collection points, or you can check out Ecobrick.org
My local town is collecting to make a composting station in a town park. I'm pretty sure your area will have something similar. It took me 3 attempts to get to the right weight, it becomes quite addictive. My top tips are choose a bottle with a wide neck, cut your plastics up, and have a great stick to push and pack your bottle.
I had to look this up too, never heard of anything like it before. Basically, it's the first half of the Pixar movie WALL-E in real life. It's truly a shame that in a time where we can make biodegradable plastics out of things like hemp and seaweed that we're still using eternal oil plastics for damn near everything.
If we had a viable way to clean all of it out of the ocean, we could probably build a trans-atlantic bridge with it all.
That's a neat project! I'm a tree-hugger as well but had never heard of ecobricking.
FYI, "Subaru Loves the Earth" is a free program at some US dealerships; you can take your cups, lids, straws, coffee and creamer capsules and snack/candy wrappers there to be made into plastic lumber: