Try the loopback test instructions from this link: http://arduino.cc/forum/index.php/topic,73748.0.html
If this passes, then you can be assured the serial portion of your Arduinos are working as expected.
Try the loopback test instructions from this link: http://arduino.cc/forum/index.php/topic,73748.0.html
If this passes, then you can be assured the serial portion of your Arduinos are working as expected.