How to get light to do this in pictures?

I'm getting a nikon d3000, and I wanna know how to create an effect like this.

Added (1).

This effect is achieved by using the flash and a slow shutter speed. The D3000 has a setting called "Night Portrait" accessed easily on the top program dial on the top of the camera. When the picture is taken, the flash goes off but the shutter stays open a bit longer to let any ambient light in. If you move the camera, or if the subject moves while the shutter is open, you'll get the blurry trails of light in your images, just like the example image you posted. It's best to try this at night or in a darkened room. This will take some trial and error but once you've learned how to create a certain effect, you'll get the hang of it.

You can get a more pronounced effect if you add flash, and the colors won't be so shifted. Use an external flash, and select slow rear sync. It uses a longer shutter speed, and then fires flash at the end.

here's a shot using slow rear sync:

http://cgipix.com/Escondido_Skate_Park_Professional_Rollerblades_Photography.htm

It is great that you're interested in learning!
Here are some way you can start:

Learn about your camera!

Read your manual! Read it several times, and practice in between. You don't have the camera yet, but you can download one from the Nikon website.

Attend a class, read some books, read/watch online tutorials.

The major camera manufacturers (like Canon, Nikon, Olympus etc) all have very useful sections on their website for learning about photography.

http://www1.nikonusa.com/slrlearningcenter/index.php

http://www.olympusamerica.com/...center.asp

http://www.usa.canon.com/...omePageAct

http://www.webphotoschool.com/all_lessons/free_lessons/index.html

Understanding at least the basic principles of photography (as well as being familiar with your camera) will enable you to make the most of your gear, and will make a HUGE difference to your images.