We all know the Apple iPhone 3G isn’t unlockable yet and as a result the Apple iPhone 3G has to be used with the provider who you purchased the handset from.
iPhone SIM card hardware unlockers are devices you attach to your SIM card and when installed it tricks the Apple iPhone into thinking you are using your original SIM, and without an software modification.
On such solution is Rebel SimCard which has apparently been tested and works with the latest iPhone v2.1 firmware, and the good thing is it only costs £10.00 that’s about $20.00.
Source — iphoneworld