Unlocking the latest firmware
Actually, sim-unlocking is pretty hard with a new iPhone. If it has the latest firmware pre-installed (2.2.1) it will come with new baseband firmware (02.30.03) which makes sim-unlocking the phone impossible at the moment.
A complete pain for those of us who want to use their shiny new iphone in Cyprus, with a local sim. A limited market I admit.
Worth checking, if you want to unlock it, what firmware is installed. Although possibly asking at the Apple shop if they have any with the older firmware might raise eyebrows.