Something new: You can transfer your phone number from one serviceprovider to another

Here in Australia, it is possible to transfer your phone number from one service provider to another. This way, you can keep your phone number with you even if you decide to change providers. 

Usually, there is are no additional charge involve in porting your existing mobile number to another service provider. You can even change the ownership of the phone number (some providers charge a fee for change of ownership).

Virgin mobile will charge $25 if you want to request for change of ownership.  Optus does not charge for the change of ownership. I heard that Telstra does not charge as well.

From experience it only took a few hours for the transfer from one service provider to another to complete and it took less than a day for the change of ownership to complete .

Some providers provide phones that are lock to their services and charge fees to unlock the phone. Some has policies that you need to consume a certain amount before they can unlock the phone for free or you need to stay with them for a certain period of time.

Virgin mobile provides unlocked phones. You can use other SIM on their phone.