iFixit

Do not yank the upper case off quickly. The case is attached to the logic board via a ribbon cable.

Lift up at the rear of the case and work your fingers along the sides, freeing the case as you go. Once you have freed the sides, you may need to rock the case up and down to free the front of the upper case. This stage can be quite tricky. Over the DVD reader are 4 tabs set back which pull out vertically.

Note that the two small tongues on the left hand front of the upper case may bend while you remove the upper case. When re-installing, you may need to bend them back to fit in the grooves in the lower case.

Disconnect the trackpad and keyboard ribbon cable from the logic board, removing tape as necessary.

Remove the upper case.

Disconnect the two antenna cables attached to the Airport Extreme card.

The white antenna cable connects to the left side of the Airport Extreme card.

Remove the single silver Phillips screw located just above the Airport Extreme card.

Lift the small silver metal retaining bracket up and out of the computer.

Peel back the orange tape on the right side of the Airport Extreme card.

Lift the Airport Extreme card up and slide it out of its connector.