I have a website layout problem, appreciate any help.

Picture a black vertically scrolling rectangular block centered horizontally. This is where the content goes. The background is gray. On the 4 edges of the block where the black meets the gray, I'd like a shadow. The finished layout would be a black block in the middle of the page with drop shadow coming off of all sides.

I have slices of the shadow, but I don't know exactly how to put it together so that all four sides have a shadow. I considered using 5 float divs, one for each of the shadows and one for the main block (in between the left and right shadows). However, how could I get the left and right shadows to expand to fill the entire height of the main block - but not extend past it?

Thanks for any input.

One way would be to make a top narrow image of your shadow (running horizontally) and put that in a div. It can be a background image in the div.
Then follow with a div that would be the content area that has a background image maybe 10px high(doesn't really matter how high) that has black in the middle and shadow on both sides. This can be set to repeat-y. It will then fill as long as you have content.
Finally a bottom div for the lower shadow.

I hope I understood your question right?

I considered using 5 float divs, one for each of the shadows and one for the main block (in between the left and right shadows).

Why do you guys always approach shadows the hard way ?? Using 5 divs just to get a shadow is ridiculous and unnecessarily complex, there are easier ways to do that.

RacerX is spot on with his method, that's how I do it too

Right on. Thanks, guys - that is a lot easier. Now if I could only figure out why Photoshop insists on cutting up my slices into two separate images...

Don't let Photoshop do the slicing !!! I don't even use the slice tool any more. I make a selection of what I want, then save the selection. It creates a channel of that selection that I can easily reload any time I need it and it's easily changed if necessary.