If you have iTunes 11 turn on the Sidebar. Go to iTunes>View and click on Show Sidebar. You can also do a Crtl+S to show the sidebar. The sidebar is where Devices appears. and Control+B to show the Menu bar
Having same problem and well I did everything AnaMusic & Illaass say to do and nothing. I even formated my devices to start from scratch and my devices will not show up on my iTunes account. I mean my iPhone seems like it's working and my iPad mini all working fine. Again when I go to my account in iTunes on my Mac no devices are showing. Will this effect me in any way down the line. Help Please.