I just ended my contract with AT&T, so now I'm selling my iPhone 4.
This is the 16GB version, model MC608LL/A. Everything on it works just fine. On the back I put a plastic protector, so it's pristine underneath. There are no cracks or scratches on the screen. Again, no issues overall.
It comes with the original box, USB cable, USB/power adapter, and original headphones with in-line microphone.
The software version is 4.3.2. In the past I jailbroke the phone and carrier unlocked it (the SHSH blobs were uploaded). So you should be able to fully unlock it again (or I can do it for you).
Asking $235 shipped payable in BTC (preferred), MtGox USD code, or Dwolla