WARNING: This is a potentially dangerous HACK and should be done at YOUR OWN RISK!!!!!
Basically, it involves placing a um506 module across the MANUAL switch contacts on your gas fireplace, allowing for X10 control. This mod can also be done on any electric fireplace rated at under 1500 watts by simply putting the unit on an appliance module (NOT LAMP).
Note: This hack has not been tested on fireplaces with the newer gas modulating valves.
Cost of project:
UM506 $18.99 OR X10 Appliance Module $15.99