Sorry - I didn't see this earlier.

The resistors are there to limit the current sourced or sunk by the PIC pins to a safe level. Assuming 5V logic, the 1K resistor limits the current to 5/1000=5mA. RS232 levels can be as high as 25V so the 22K resistor limits that current to 25/22000=~1mA. You can leave them as they are or you can replace the 22K with 1K. If there's any chance you'll connect it to RS232 levels, keeping the 22K is safest.

Check the PIC datasheet to see the maximum current limits for each pin.