iTunes on PC was used before to sync and update my iPhone 3, iPhone 4, iPad, iPad 2, but recently I got an iMac 27 and started sync'ing the iPhone 4S using the iMac. But when I plug in the iPhone 4 (the old one) into the iMac, then I can't drag Music, Movies, or iTunes Univ videos into this old iPhone. (in iTunes 10.5 on the iMac, I can't drag and drop any Music to the iPhone 4 under DEVICES)
What is a proper way to start sync'ing with the iMac if it was sync'ing with the PC before? I just want the iPhone 4 "as is", but sync'ing to the iMac instead of the PC. (want to keep iOS 4.3.5 because I might do some development work and want to test on iOS 4.3.5) Are there other precautions to take note of when changing which machine to sync to?