If you can get that type of control over the LPT-port you could definitely bit-bang it but wouldn't it be easier to use the serialport on the PC in conjunction with a MAX232 to bring the voltage of the line to the correct level? Depending on your actual need you may even be able to skip the MAX232, have a look at the SERIN/SEROUT sections of the manual, it'll tell you the details. Make sure you have the correct polarity (Inverted vs True) depending on if you use the MAX232 or not.

/Henrik.