"In practice the IMEI can readily be changed in seconds by criminals with little technical knowledge, using a PC with the right connector for the phone and suitable software that can be obtained via the Internet. The reprogrammed phone is back on the street with its new serial number in minutes, often before the original serial number has been blacklisted."

Andrew J Winks: - Changing the IMEI humber is no where near that simple and hasn't been for a good few years. It used to just be a case of connecting the phone up to a computer and as you say, using easily downloaded software you could change the IMEI number. The IMEI number is no longer stored in the general firmware area (where you can set network locks, or flash the phone to remove operator specific software builds) but is now on a seperate write once chip, the only option is to unsolder that chip, replace it with a new blank one and program on a 'safe' IMEI number. Its not a simple operation and takes a fairly sofistacted setup with someone that knows what they're doing. I know this has been the case for Nokia, Samsung and Ericson phones for at least 3 years now.