I see it has a serial cable. Does the serial cable need to be plugged into a PC, or does it recieve the X10 signal like an X10 transceiver by being plugged into the wall? I would prefer to use the Powerlinc USB & no serial if I can help it.
I use it plugged into an electrical outlet, no serial cable.
If its too strong, is it possible that I could pick up my neighboors X10 remote controls (I am planning to use the X10 device to Insteon translation via software) if they have them & have them turn my lights on & off?
Absolutely. You should change your house code if that's a possibility.