1. The language and tone used above is not necessary.
2. You will lose your contact info. You will need to sync it in order to get the info back on the device.
3. Actually, the restore information is in the thread that was referenced:
How can I restore my iPod Touch or iPhone should something go wrong?
Connect your device to your computer via the included USB cable. Open iTunes, click on the iPod or iPhone icon on the left, and click the big restore button somewhere towards the middle of the application. After a short period of time, your device will return to its factory settings.
Unlocking services is a different thing altogether which can potentially cause changes in your iPhone that a restore cannot reverse. As a result, when firmware updates disable the phone functions of an iPhone, the hacking community can generally figure out a way to restore your iPhone to its true factory state.