Image Stabilization is going to be your new best friend, and in my opinion, a mandatory tool in every photographers arsenal. Image Stabilization, or 'IS' for short, can help you get a much sharper images then normally possible when hand-holding a camera. In fact, it's so important to helping me get great shots I won't buy a lens or camera without it. In fact even my point-and-shoot G9 has IS built-in. Both Canon and Nikon offer fantastic image stabilization. Canon uses the term IS (Image Stabilization) and Nikon's VR (Vibration Reduction). VR and IS are the same, and both terms are interchangeably. Each camera manufacturer uses their own acronyms. Both IS & VR stabilizes images from the unsteadiness of hand-holding a camera. IS helps you times using a tripod is not possible or practical, IS lets you shoot in bad light and slower shutter speeds.
How it works: Now I'm not a expert of techincal operation of IS, but here's my best attempt at the techincal way it works. Image stabilization helps to steady the image projected back into the camera by the use of a "floating" optical element—often connected to a fast spinning gyroscope—which helps to compensate for high frequency vibration (hand shake for example) at these long focal lengths. Sorry thats as technical as you can get from me.. :-)
A new comer in the DSLR market is Sony which has moved the Image Stabilization normally contained in the lens to the camera body itself.(formerly technology developed from Minolta). The stated advantage is not having to to buy lens with the expensive IS technology.
IS and VR work great for subjects that hold still, However, image stabilization does not prevent motion blur caused by the movement of the subject or by extreme movements of the camera. Image stabilization is only designed for reducing blur that results from normal, minute shaking of a lens due to hand-held shooting. Image Stabilization does nothing for fast moving objects such as sports, and small children. :-)
Image stabilization technology, has recently become more and more available to the average photographer. Over the years, the technology has greatly improved, and is available in a much wider range of cameras and lenses from several different manufacturers. IS is an enabling and liberating technology. It helps photographers of all abilities get noticeably better results.
I highly recommend Image Stabilization.