I'm trying to upgrade my iPhone OS system in my 3G to version 4. I updated iTunes, which was required. However when I go to upgrade to OS 4, I get a message for several minutes saying that that the phone is being backed up before eventually getting a message saying that the upgrade could not proceed. I've tried it several times and got the same result. I gives me the option of proceeding without backing the phone up but I'm nervous about doing that without further explanation. Has anyone run into this? Thanks.