pcb-mode

PCB mode is a major mode for editing files for the gEDA PCB program within
Emacs. To load it automatically for both footprint (.fp) and pcb (.pcb)
files, add the following incantation to your .emacs:

  (let ((pair
         (cons (concat "\\." (regexp-opt '("pcb" "fp"))) 'pcb-mode)))
    (setf auto-mode-alist
          (cons pair (remove pair auto-mode-alist))))

If you don't want to load this file every time Emacs starts, you should
ensure it is in your load path and then add the following form:

  (autoload 'pcb-mode "pcb-mode" "Mode for editing PCB files" t)

For more information on usage, see the docstring for `pcb-mode'.