http://i173.photobucket.com/albums/w67/143house/courtyard/window.jpg

It's an existing concrete block wall, I have installed a new window and
above the window is the tie beam and there is a soffit and roof structure
above the window.

Where I labeled the word "Here" is where I am having trouble.  I need to
form a strip of concrete overhang along the top edge of the window, over the
wood framing.  I need to do this because there are three other equivalent
size existing windows that looks like that along that wall so I need to
match it.

I can see screwing a 2x4 along the bottom edge of that concrete, do I just
then scoop concrete into the slot until it fills up and finish it flat?
Seems this would be difficult to do I remember last time I was doing this
there were more spillage on the ground then there is in that narrow space.

Someone mentioned to me to have a piece of wood at the bottom, then spray in
those foam to fill up the space, not all of it but most of it, then use
concrete to fill in the rest?

Thanks in advance,

MC

Think stucco rather than concrete. You'd frame it with wood to within
1/2" or 3/4" of the finished dimension and then install casing bead,
corner bead, and lath (if necessary).

Pay close attention to construction details (weather barriers, flashing,
etc.) to ensure that moisture is handled properly.

As others have suggested, you need to consider stucco and stucco techniques.