I recently purchased a new iMac and all my old data is on an external drive which I cannot hook-up to my new machine yet because the firewire doesn't match.(Old firewire 400 cable and now have new firewire 800 port). So my question is such, when I try to update to version 4.1 on my iPhone 3g iTunes tells me to save my purchased items before updating, so how do I save my purchased items and what happens if I don't save them first and update anyway?