Taking photos of a concert?

I'm going to a friends concert this weekend maybe, and besides moshing, I decided that I'm going to try to take awesome looking photos for the bands. I was just wondering what settings I should use to take nice, awesome, action-shot like photos of bands. I have a Nikon D90 (it's my fathers, but I use it now) and I don't really know much about it.It'd be great if someone can tell me how to set my camera up so its ready to take awesome concert photos.

Things to note (may or may not matter)
-The room will be darkish beside little stage lights possibly
- I don't have any more lenses then what it has on now (as to whether its a different lens then what it actually came with, I'm not sure)

Also, would it be advised if it's a dark room to bring a sock to cover up the flash? I know a lot of people do that, and one of the photographers at the last show had a sock covering up his flash, his pictures came out amazing.

You're bringing your father's Nikon D90 to a mosh pit?

Apart from the obvious risk to your camera, the mosh pit is not generally the place I would choose from which to shoot concert pictures.

Nevertheless, if you do it, put your ISO as high as it will go without noise becoming objectionable. Bring your fastest (large aperture) lens and shoot with it wide open. Meter on the performers. If it's dark, your camera's light meter will try to make the blacks gray. This will result in the performers being blown out.

Putting a sock over the pop-up flash? How inventive. Forget the sock. Shoot with the camera on aperture priority mode and you won't have to worry about the flash popping up. Or use the flash as is if the venue allows it. The on-camera flashes have very limited range. Think 8-10 feet. If you use this wildly popular (to hear you speak. "podiatral" diffuser technique, it's going to reduce the range greatly.

Set the largest aperture to let as much light in as possible, you'll probably need to increase the ISO to a point where the noise is quite noticeable. Forget the flash it'll be next to useless and if the band uses any form of stage smoke it'll just light that up and reduce the contrast. Concentrate on the areas that are lit the brightest and use spot metering. If it's a kit lens fitted, you'll struggle to get shots that aren't motion blurred, without ramping up the ISO.

Sock on a flash? Interesting!