Hi,
Since you apparently needed a levelshifter/inverter to get the Pi talking to the PC it means that it must output a non inverted signal at logic level (3.3V?) - which is exactly what the USART in the PIC outputs and expects as input (on some PICs you can even invert in hardware if needed). So, it should just be a matter of connecting TX to RX, then you could use HSERIN to receive data from the Pi - for example.

/Henrik.