How to take a photo in the sunset?

I'd like to take a picture like this:
http://people.desktopnexus.com/wallpaper/490645/
What settings do I need?
My camera's a Nikon D300
I want my silhouette to be black, but my skirt (it's lace) to be lit.

There are no magical settings… All test and find the one that works for you…

The method to capturing a picture like that is to decrease exposure by increasing shutter speed. Since you want to capture the sunset, the amount of light is relatively higher than when taking a picture of an indirectly lit object. Since you're giving less time for light to be captured, all other objects which aren't emitting light become much darker in the photo, hence the silhouette effect.
Also, if your camera captures pictures in raw format, you can fine-tune the colors and other aspects of the image in software such as Adobe Camera Raw, which is rather easy to use and much simpler than Photoshop.

Firstly, shoot in manual & use spot metering.

Meter on an area of sky similar to the tones you want to reproduce (NOT at the sun!).

Drop the exposure by a stop or so.

Then using off camera flash, light the lace skirt to the level you require. (Radio triggers to fire a manual flash off camera can be had for about £20).

Same principle used in this shot of mine - the ambient light was dropped & the subject flash lit;

you just need to light your skirt though.

.In our own backyard Here at Sunset headquarters in Menlo Park, California, we're always looking for ways to green up our offices. We started recycling back…

Expose for the sunset and let the subject go black

Expose for the background, then the foreground will be in silhouette.

IN the sunset? You're going to get hot! Lol

You can easily do that. Since you own a D300, I'm going to assume you know all about aperture, shutter speed, ISO, etc. (basic photography principles). Spot meter on the sky (NOT the sun itself), then set the camera manually to the settings recommended by the meter. After that, adjust the camera according to how the shot looks. You might also end up bumping up the sat and color in Photoshop afterwards.