[rainfreak]

You are correct, and therefore not as much of an idiot as you thought.

When you jailbreak an iPhone, you are doing the equivalent of rooting an Android device, meaning that you gain access to system files on the device that are normally locked from the manufacturer. This allows you to make many more modifications to the device that are normally not allowed to be done. In the case of the iPhone, this includes installing apps from sources other than iTunes, modding the home and lock screens, free WiFi tethering, etc.

When you unlock a phone you are opening it up to work on a different carrier, using the same type of service, than the one you purchased the phone on. This includes unlocking an iPhone from ATT to work on T-Mobile and the same goes for an iPhone from Sprint to work on Verizon (or vice versa). ATT and T-Mobile use GSM and Sprint and Verizon use CDMA. That means the technology has to be the same for the iPhone to work on the other carrier, so an ATT phone will not work on Sprint or Verizon and a Sprint or Verizon phone will not work on ATT or T-Mobile.

In the end, unlocking and jailbreaking are indeed two totally separate things with two totally separate results.