I'm a (very) amateur photographer- this past summer I bought the Nikon D3000 and it included the NIKKOR 18-55mm kit lens.  I'm looking into buying a new lens, for sport photography, where I'm about 50-100 yards away from the action- my lens now doesn't give me enough zoom to get great shots without a lot of cropping.  I'm primarily interested in the NIKKOR 55-200mm lens (found here).  Does anyone have any experience with this lens, and knows if it will be good for my purpose?

My more pressing question is this: how is it that lens can have the same focal length and be made for two different purposes?  At the Nikon website, there are lenses under “close up lenses” and under “high power zoom lenses” that are both 200mm.  How can this be? How can I tell the difference and make sure I'm getting the type of lens I want?