Without knowing your capabilities it is hard to answer such a general question.
If you are familiar with Python and can program the 8051, it should be relatively easy to have the 8051 receive a byte and control up to 8 outputs based on the bit values in the Byte and then have the 8051 echo the value back to the PC for output status confirmation.
I have not used Pyserial or Python but from what I have read Pyserial should be able to easily send and receive byte in this fashion.
Good Luck.