I cannot get the majority and all of my paid for apps off my iphone 3gs and onto itunes (an imac). It says my computer is not authorised even though it is. Have tried deauthorising and reauthorising, and a restart of imac. Also tried to use my previous computer, a powerbook but no joy. This is driving me mad as I have a few paid for apps I'd like to stick on my new iphone 4, any thoughts would be greatly appreciated.