Making a cold air intake???

Hey does anyone know how to make there own Cold air intake...is it worth making your own? Its for a stock 99 escort SE.

I got an LX.....lemme link the PCI (Pringles Can Intake)

http://img.photobucket.com/albums/v290/Jet-Lee/CAItop.jpg

and it comes out the bottom. The opening for the intake silencer has been routed to the vent in the front bumper.
http://img.photobucket.com/albums/v290/Jet-Lee/CAIbottom.jpg

I lost 1-2mpg(down to 27-29), but I can feel a little more pull at the top end, surprisingly. Not much, but it's there.