So you're getting an iPhone 4S, you've chosen the carrier and decided on the storage size, and now you need to figure out the ins and outs of how to sell your old iPhone (or other smartphone) before upgrading? If you don't want to keep it around as a spare, or as an iPod touch, or hand it down to a family member or friend -- if you're looking to get some cash back -- then there are a few things you can do, and a few things you need to know before getting started.
Today we're going to show you how to cash out the old and bring in the new using a number of great services!