They’ve been making a lot of progress figuring out how to carrier unlock the iPhone. Appareantly they’ve been working on reverse engineering the firmware that controls the core phone functions of the device.
In the meantime, someone has figured out a way to create a hacked SIM that will allow you to use your iPhone with a range of GSM carriers that use a compatible SIM format.
It sounds like a bit of a kludge to me, but hey, if it works, I figured some of you would be interested.
Update 8/21: The iPhone has been fully unlocked, without resorting to this SIM kludge, but there is still some work to do before it becomes practical for the average person.
wakey wakey
other iphone sites are ahead of you
http://www.iphoneworld.ca/news/2007/08/14/unlock-iphone-for-any-carrier-with-turbosim/