This is very beginner project on how to read analog DC voltage with PIC and display it on LCD display developed by sprut.
Voltage is read with 10 bit ADC input. Input is connected directly to RA0 pin so be careful with measured voltages. Higher than VCC voltages may damage PIC microcontroller. If you are not sure better connect protecting Schottky diodes on the input. ADC can measure with 4.8828125mV accuracy when VCC=5V. Download assembly source code if you want to experiment more. sprut also has more info on his site about electronics, PIC microcontrollers. Site is in German language, but any online translator can help.