I have the iPhone 3GS, iPad 3G, iPhone 4 (in transit) and a micro sim adapter. I would like to use the new micro sim from the iPhone 4 to use on one of these three devices at a time as I choose. Is this possible? I'm aware of the changes to the iPad APN that needs to be made. Also, if the new micro sim will not allow me to do it, can I just cut my exising sim from my 3GS and use on the iPhone 4 instead? Main concern is AT&T detecting and either charging me additionally or disabling data plan on my account.