If you haven't seen The Story of Stuff, you absolutely need to. And if you've seen it but it has been a while, I encourage you to watch it again. It will inspire you to make a change in your life. It's about twenty minutes long, but worth every second.
If you are looking for some practical ideas to make a change to reduce your global impact, I recommend you check out Rubbish Free Year. It's a neat idea. This couple in New Zealand challenged themselves to not produce any trash for a year. They ended up with only one small bag! That's amazing!
Hopefully you will be inspired.