Everytime I power up my Niknon D3100, it makes a clicking noise (usually a series of three or so). If you are looking thru the lens you can see some deflection. This happens with both lenses that I have.
These are side effects of image stabilisation, or VR (Vibration Reduction) as Nikon brands its own implementation of it. VR works by shifting some lens elements in the opposite direction of the movement of your hands to counteract that very same movement, thus aiming to allow you to shoot using lower shutter speeds than otherwise possible with the same lens. While mid and high end lenses often allow more than "on" and "off" - some newer super telephoto models have special VR modes that reduce the shakiness in the viewfinder, yours (if we're speaking of kit lenses) will most probably have just on and off positions.
Look for a switch with "VR" labelling on the left side of the lenses and try moving it to the "off" position - the noises and viewfinder shakiness should disappear. This is, however, just to confirm that VR is the source of the "issue" - it may be a better idea to normally keep VR on.