Tips for shooting basketball inside a stadium?

I have a nikon d3000 with a 18-55mm lens and a 55-200 mm lens

You're going to need a fast shutter speed to freeze the action. Use shutter priority mode.

Both these lenses do not have a large maximum aperture. To freeze the action a high shutter speed is required. You did not say what DSLR body you are using. If you are using one that was release in the last 2 years, you could increase your ISO to 1600 or even 3200. You will not be able to enlarge the picture beyond postcard size without noticing the grains or the loss in details.

I suggest you try out the setting before the game to see if it is acceptable to you.

Another tip, if you shoot at the player running towards you, you can get better shots as there's 'less movement' than if they are running across you.