Your microcontroller can take only TTL serial communication. The PC use some different logic levels for serial communication. You have to use a serial to TTL converter. Use conertor IC, MAX232.
Connect the serial port of PC to MAX232 IC via DB9 connector, then MAX232 to the serial pin of your microcontroller. Use any software like hiperterminal, putty etc. to see the data coming from the controller, or to send data to the controller