Smartphone retailer Carphone Warehouse has today revealed it will launch a mobile network later this year called iD. The service will be what's known as a "virtual" network and will piggyback off Three's service in a similar method to GiffGaff. Carphone Warehouse hopes to lure customers with a couple of enticing offers -- notably the option of 12-month contracts and free international roaming. The latter is a service already offered by Three. But iD's pitch is 22 countries (as opposed to Three's 18) including the USA and Australia.