US-centric: Recycle your old electronics for free with the US Postal Service's new "Mail Back" program. The program, which allows you to discard your used electronics in an environmentally friendly manner, provides free envelopes in 1,500 post offices to handle everything from inkjet cartridges to cell phones and MP3 players. The postage-paid Mail Back envelopes are located in post office lobbies, and you can take as many as you want for free. Currently the pilot program supports 10 areas, including Chicago, Los Angeles, and Washington, D.C., but could go nationwide this fall if the trial is successful. If you're not part of the pilot program, you can still recycle cell phones, computers, and more if you know where to look.