I have an iPhone 5 that I'm planning to sell to Gazelle (I'm upgrading to a 6). You receive more money if you sell an unlocked phone, of course, and this seems fairly easy to do with AT&T. I just have a few quick questions first: Can you still use AT&T's service after unlocking your phone? In other words, should I do this now prior to receiving my new phone next month? Also, I have been an unlimited plan still. Will unlocking my phone affect this? Any other contract issues I should be aware of? Thanks in advance for the help!