Since I like to get a new cell phone every time my contract comes up for renewal, I am always left with an old phone that works perfectly but is useless to me; it's like having outdated jeans, you could keep them but you know you'll never wear them again.
There are several options to recycle your phone, but before you do, remember to erase your personal information (recellular offers a free eraser):
1) If you want some money for your cell phone as you recycle it, then try Cell for Cash. It's not much, but it may pay for (almost) a gallon of gas. You can also donate a portion of the sales price to the charity 911 cell phone bank.
2) One of my friends is in the military and she says that most of the people in her unit can't afford the cost of cell phone bills for overseas calls, so no one calls home unless it is an emergency call. You can actually support our troops overseas by sending your used cell phone to Cell Phones For Soldiers; they will recycle the phones and send out calling cards to the soldiers. The program gives us all a way to recycle cell phones and help the soldiers at the same time and has now grown to a non-profit that expects to raise nearly 9 million dollars in the next 5 years to send out calling cards and even prepaid video phones to soldiers stationed abroad. Not bad for a company started by a 13 year old!
3) If you have a charity you would like to donate your used cell phone to, then check out Charitable Recycling (they also recycle ink cartridges); their list of charitable organizations includes everyone from animal advocates to women's shelters, and includes local charities ranging from local fire departments and schools to hospitals and children's services. If you can't decide which one, you can simply donate your used phone and they will distribute the proceeds. If you want to start your own drive for your favorite charity they even help you set that up.
Recycling is good for everyone, so don't throw your old phone away, give it a new life. You may even help save someone's life by giving it to a charity.