We all know how to connect our Kindle to the computer so it can charge. That USB connector will only fit a certain hole, so you can't go wrong with that. And while the earth won't open up and swallow you and your Kindle if you just jerk the cable free when you are ready to use it again, it is good to know the polite way to remove your Kindle from its USB connection so you don't need to worry about losing anything.
PC Users: Click the Start button, then click Computer and look for your Kindle. Right click on the Kindle drive and choose Eject. Do NOT disconnect the USB if you want to let it continue to charge.
Mac Users: To safely remove your Kindle from your Mac, drag the icon to the trash. You will see the pointer change to an eject button when you have it over the trash bin... drop it (let go of the mouse button when it is over the trash) and the icon will disappear, indicating you can safely disconnect the USB cable. Do NOT disconnect the USB if you want to let it continue to charge. You can tell your Kindle is full when the charge light on it changes from amber (charging) to green (fully charged).