Cash In On Your Old iPhone
With the introduction of the new iPhone 4S, we're bound to see a number of older phones being offered up for sale. That said, a large number of phone owners (iPhones and others) will simply put that old phone on the shelf and forget about it.
Don't save it, sell it.
According to CNN Money, old phones, particularly iPhones, are a valuable commodity, not just for their market value, but also for the precious metals contained inside.
Before you sell your old phone, be sure to clear it. Trade-in companies say they wipe used phones, but you should make sure it's done prior to shipping. If you're not sure how to do this, take it into a service center and ask them to do it. Yes, it may cost you a couple of dollars, but it's cheap insurance for protecting all of the personal information you've put on that old phone.
If your phone isn't worth a trade in, consider donating it to any number of charitable organizations that will repurpose the phone or use it to help buy calling cards for US service members.
Either way, you win.