VR stands for vibration reduction. There is a motor inside the lense that comes on to counteract movement so you can get a steadier shot with less lens shake/blur when you are forced to use a lower shutter speed in low light conditions.
FROM NIKON
VR
Vibration Reduction (VR)
This innovative VR system minimizes image blur caused by camera shake, and offers the equivalent of shooting at a shutter speed three stops (eight times) faster.* It allows handheld shooting at dusk, at night, and even in poorly lit interiors. The lens’ VR system also detects automatically when the photographer pans — no special mode is required.
Check out this link. It shows you how VR works. has a few example shots with and without VR activated.
http://nikonimaging.com/global/produ..._if/effect.htm
http://nikonimaging.com/global/produ...mmf_35-56g_if/