Nikon d5000 lens for close up photography?

I have a nikon d5000. I want to buy a lens that i can use for very up close photography. For insects and flowers for example. I'm not sure which one would be the right lens for these types of pictures.

Http://www.nikonusa.com/Nikon-Products/Product/Camera-Lenses/2160/AF-S-VR-Micro-NIKKOR-105mm-f%252F2.8G-IF-ED.html

They are called macro lenses and come in a variety of focal lengths. The longer the lens the further away from the subject you will be when shooting 1:1 image to subject ratio images.
Here are the lenses:
http://www.nikonusa.com/...index.page
Of the lenses listed, you will probably want to buy one of the AF-S lenses to retain auto-focus, however once you start shooting at image to subject ratios of 1:4 or closer, you will want to be in the manual focus mode.

1) Macro - personally, i use a Tamron 90mm macro f/2.8
2) bellows - you can use an existing lens