Quote Originally Posted by Atom058
I believe that I need to get the incoming voltage to the ADC pin to 5V or below. Isn't that correct?
In fact the Vpeak must be lower than 5 volt. So a Vac(rms) of 5*.707=3.535 Vac(rms)

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?
Yes. Maybe a dual secondary transformer (like the one you used for the DImmer) could work. This will also provide your insulation. So you use one output for your PIC and plah plah, the other for your reading.

Maybe it will work good... maybe not... in theory yes... but i feel some potential bugs... interesting to know your results.