I have a Nikon D80 digital camera, and I love it! But my only problem is I can't figure out how to get the black shadow to go away behind people. It only happens when I hold the camera diagional. If I hold it horizonal there aren't any shadows behind the person. I've tried bouncing the flash on the ceiling, doesnt help, also I've tried putting the flash in different directions still doesn't go away. Anyone have any advice on how to get this shadow to go away??

You will never get it to go away with a camera mounted flash when in the vertical position. You can HELP to soften the shadow by a good diffuser on the flash such as the Gary Fong Lightsphere, which I use by the way. But it is just simple physics, when the light is coming from the side of your subject, there is going to be a shadow behind and to the side of them. You have to do one or all of these things to prevent it:

Get your subject as far away from the background as possible.

Get the flash on a bracket where it will remain in an "upright" position no matter how you orientate the camera body.

Even with a bracket, you should still use some diffusion on the flash to prevent the harsh look of direct flash.

I will add that shadow is not some kind of evil thing to be avoided. Shadows are a natural part of life and can add to the dimension and beauty of a photo. A soft edged, diffused shadow is not at all distracting, so I feel the main thing you need to do is properly diffuse your flash rather than being concerned with trying to totally eliminate all shadows, which is actually un-natural looking.

steve