You must first remove the dash cap in order to remove the front speakers.
To remove the dash cover, look under the front edge (the passenger compartment end). There are, or should be, five screws with 3/8" nut heads if I'm not mistaken: one on each end (the driver side and the passenger side) and three similar screws in the middle of the dashboard. Remove these five screws, then tilt the steering wheel down out of the way. You then grasp the dash cover firmly at about shoulder width or so, and gently but firmly pull the cover towards your chest. It should release from the two snaps at the front of the cover where the cover meets the windshield. You'll be able to see all of this once the cover is removed and in your lap.
Be careful when handling the cover - it is a vauable item and expensive to replace. The last I saw it was sellling for over $450.
_ken