How do I safely eject or unplug an iPad, iPhone, or iPod when iTunes is not running?
In the Finder in Mac OS X, press Command-Shift-G to Go to folder. Type /Volumes. This will take you to the “Volumes” folder. If your iDevice is mounted as a drive, it will appear here. You can select it and press Command-E to eject it. If it does not appear here, it is not mounted as a drive, and you can simply unplug it. Note that it may or may not appear on your Desktop or in a Finder sidebar depending on your settings, but it should always appear in the /Volumes folder.

On Windows, in the system tray, there is an icon you can click to “Safely Remove Hardware and Eject Media.” Right-click the icon, find the name of your iOS device, and click it to eject it. If it does not appear on this list, it is not mounted as a drive and you can simply unplug it.