Steve - Thanks for the diagram. It looks to me to be a modification of the transformerless power supply with the addition of a resistor divider network to provide the input to my PIC. Is that correct?

I don't intend to power my PIC or anything with this - so the current capability of the circuit is not important. I just need to know how to condition the AC so that I can read the voltage.

I like your idea of triggering an interrupt (like for the AC Lamp Dimmer circuit you helped me out with), waiting a few uS and then start measuring the voltage on an ADC input. I would then find the highest value and from that I can calculate the voltage. However, I believe that I need to get the incoming voltage to the ADC pin to 5V or below. Isn't that correct? That seems to be the $64 question... how do I get the 120V AC input to some level that is acceptable for an ADC input? Is this accomplished with the resistor divider circuit that you presented?

I appreciate your help!

Thanks!