How to take a picture like this? - 1

I recently got a nikon d3100 and i want to learn some cool techniques and this is one that looks really awesome, so if you know how please help, thanks.

That one is done with a long exposure. See if your camera allows that. You'll need a tripod or everything will come out blurry.

It's called light painting or light graffiti.

1. Get out camera's manual and read about setting for long exposure (10 seconds or more)
2. Wait until it's dark outside
3.mount camera on tripod
4.set for long exposure (shutter priority, long exposure.iso and aperture ar less important)
5.stand in front of lens with light source and move light source.

Practice a few times and you too can do light painting and be cool!

Sometimes you can take it with a regular camera but you just hook it up to a computer and they just add effects to the photo

That's not light painting, just cars moving at night and perhaps a star filter. I think your camera allows fully manual mode; set your tripod at a corner and the shutter speed about a few seconds long

I highly recommend you buy the book understanding exposure from Bryan Peterson. It will explain a lot of things you will want to know to get the most out of that camera. It will explain the four things that make up the exposure. Available light, shutter speed, aperture, and iso and the effect each have on the photograph. I read this book when I first started out and learned a lot of valuable information. I think it is the best book for a beginner.

That photo was done with a slow shutter speed which allows you to show movement. The lights from the cars passing by are captured in streaks but because the car wasn't there long enough you don't see the car. The easiest way to replicate this is to put your camera on a tripod (needed so your movement doesn't cause blur) put the camera in Tv or Sv depending on your brand, set the shutter to 5 seconds and press the shutter button. Your camera will record the scene for 5 seconds. If you need to set it for long go to 10 seconds. The longest the camera will allow you to set it for is 30 seconds which is probably what the camera was set to for that photo.

It is simply a long exposure.
Stick your camera on a tripod to hold it steady.
Set a fairly small aperture (f8 or thereabouts) and low ISO to avoid too much noise.
experiement with different shutter speeds from about 1/2 second through to 20 seconds depending on the actual subject and lighting levels.

Nicole - run along and leave this place for adults please.

I'm not going to repeat what others have said but you definitely need to learn about your camera. When I was in college the teacher stressed to us to all sit down at home and sit and read our camera manuals with our cameras beside us so that we knew how to do everything.Me and a couple of others did and when we showed our images to the class a few months later she could tell who had taken the time to sit and read the manuals and who hadn't. It made the others really think and more people read them too. The difference is amazing! You will get better pictures and also feel a lot more confident and in control, giving better pictures anyway. I really can't stress it enough and it may seem boring, maybe stupid and silly but if you do, people will notice. It will tell you how to do a long exposure, along with many other things you probably don't know your camera even does. I found learning about my camera very interesting at times and now whenever I get new camera, whether it's a DSLR or small film camera, I sit and read the manual even if I think I know it all: P which I never do!