Does the garage have a separate meter from the utility or a separate panel? If it's a meter then you probably wont get X10 to travel over the power lines but it might it’s worth a try.
Buy a PAT01 transceiver an appliance module and a palm pad remote. First plug in the module in the garage and the PAT01 in the house (try getting it on the same phase) send a command with the Palm Pad and see if it works. If not plug the PAT01 in the garage you should just be able to get 75 feet, if not you can modify the PAT01 for a bit better range using tips found here
[Link: geocities.com] modifications PAT01 is the same as RR501.
Bill
www.homeautomationnet.com