Not long ago, I forgot how -- perhaps inserted in my New York Times -- I obtained a couple of cell phone recycling envelopes from the Motorola Race to Recycle project.
Basically, the idea is this: In a Netflix- or Snapfish-like self-mailer, postage paid, you can send in your unused cell phone to be recycled and reused. You should take out your SIM card, and you can include your battery if you'd like -- but if you send in a phone, you'll help raise money for K-12 education programs.
I'll send in my old cell phone tomorrow. It's been sitting on my kitchen counter for a year now, unused, and this was a good excuse to transfer all the old numbers to my new phone, which I hadn't done yet. Also, it's hella better than throwing the phone away.
Recycle your old phones! Kudos, Motorola.