Bricks, Masonry, Asphalt and Concrete - Pad for concrete porch

I posted this in the decks, patio's and porches as well, wasn't sure which was more appropriate:
I'm building a porch using 2 rows of concrete block (with footings) and I'm wanting a 4" thick pad for the deck. The porch will be 48" deep by 64" wide. The only way I can think to create the pad would be to build a form with the correct dimensions with a plywood bottom and removing it after it hardens. My question is is there anyway to pour the pad in place or a better way to accomplish the final product? Thanks.

Could you describe what exactly you are doing, will the porch be hollow under the concrete? will it be 16" off ground level?
Frank

The foundation will be 16" off ground level and the pad an additional 3 1/2 to 4 inches above that. I was originally thinking of leaving the base hollow and making the pad separately in a form and then placing this on the base. Some else suggested it would be easier to fill the base with compacted sand and pour it in place. The reason I was considering the orignial plan was that I would like a slight overhang of the pad over the base and thought that was the easiest way to accomplish that. If I pour it in place I would think that having the pad even with the outside of the foundation would be much easier than framing for an overhang.