Apple announced the iPhone 3G, and immediately after that everyone wanted to know if the 3G would be as easy to unlock as the original iPhone. It wasn't allowed by the firmware that Apple had preinstalled on the newly shipped iPhone 3G. The firmware was updated enough that it made it very difficult to unlock the iPhone 3G.
Many phones are designed to work with a single service carrier, such is the case of the iPhone 3G. The methods that were developed to unlock the iPhone 3G were able to remove the carrier restriction, along with unlocking many new features. The process was not as easily exploited as with the original iPhone.
By tricking the iPhone 3G into thinking it had a test SIM card inserted, some people were able to unlock their phones with a special SIM card. There are now some relatively inexpensive devices that allow consumers to bypass the locks on locked features via SIM card. These can be found online relatively easy.
It wasn't until later on that someone figured out how to use software methods to unlock the iPhone 3G. Fully unlocking the 3G took time and patience to crack. Some companies are still trying to figure out how to unlock the 3G through a software type solution to profit from the phone's success and locked features.
If you want an unlocked iPhone 3G relatively soon, there are a few options you can take that are not free. There are many companies that want you to pay them for their hard work on allowing you to unlock all of the iPhone 3G's capabilities and service options. You can always buy an already unlocked iPhone 3G from an auction site or classified.
Eventually there might be a free solution to all of the iPhone 3G unlocking problems. For now, there are cheap services that can help to unlock your iPhone 3G with little or no consequence on your part. The future holds many surprises, maybe they will release a better iPhone or Apple product soon enough that unlocking the iPhone 3G will be something everyone could do inexpensively.
Closing Comments
The iPhone 3G has some options available to unlock and add functionality. It is not hard to decide whether or not you wish to unlock your iPhone, just do some research and find out what you're missing.