Chances are, your cell phone is tethered to one particular service provider. If you try to leave that company, your phone won't work. It's locked. If you travel to another country and try to use another company's cell phone service on your old phone, that won't work either. Locked again.

It doesn't have to be this way, though. Depending on what kind of phone you have and what company you purchase cell phone service from, you might be able to unlock your phone. Then, you'll have the freedom to use the same phone with different companies, or switch phone numbers and service accounts.

­If you've ever wondered what the difference between a locked and an unlocked cell phone is, or if you've ever wondered if your phone can be unlocked, or how you can do it, we'll explain it to you in this article. Plus, we'll tell you why having an unlocked phone can be a good thing, and whether or not it's legal.