Uh-huh, cept it stays on the screen, it's not just a pop-up dialog box.
Go to Display->HeadsUpDisplay->PolyCount.
Faces is the number of polygons, Tris is the number of triangles that would be after they're all divided (like they need to be for certain other applications, games, RealFlow, etc, etc)
Similarly, you can just type "polyEvaluate -f " without the quotation marks into the command line at the bottom left of the screen.
Maya's help is your friend, trust me, use it.