RX blink LED

Hi, I have a Arduino Mega reciving information true serial from my computer and when something is sent to the Arduino the small led on the board blinks. So i was wonering if there is some way to make a normal 5mm led blink when i recive informaiton from my computer.

AFAIK the connections for the Rx LED are not brought out to any of the I/O pins.

What is the purpose of using an exxternal LED?

Would it be sufficient to write some code to flash an LED after checking Serial.available() ?