Apple has sold over 2 million iPhones since they first released their latest gadget 9 months ago. Apple Estimates that about 20% of the iPhones they sold are being unlocked. Many of these end up broken or 'bricked'. Unlocking and jailbreaking is very popular amongst the iPhone users.
With an unlocked iPhone you are able to use the iPhone on any GSM network worldwide. It breaks the phone free from the expensive AT&T contract, and allows users to use their own preferred network anywhere in the world. Jailbreaking allows users to install third-party applications witch, by default are blocked by Apple's software.
Dr. R Smits warns against the many downsides of unlocking your iPhone. There are many unlock solutions available online, often people download a piece of software from an untrusted source that promises to unlock/jailbreak their iPhone. In many occasions people do not understand what the software does exactly, leaving the expensive gadget bricked and useless. Unlocking can have many benefits, but be sure you understand what you download, and what the software does before you attempt to unlock it. You dont want to end up with a $500,- brick.
Robert runs an iPhone Unlock & Repair Service. You can find more information at iPhone Sim Unlock.