Arduino question

Is there a way to send commands to the arduino over a serial connection. I want to be able to control a servo via a serial connection to the computer. My arduino will be here Thursday along with a breadboard wires and a servo. Thank you very much.

You will need to shift the voltage levels because the RS323 serial port uses positive and negative voltages higher than Arduino can accept. You want 0-to-5V (TTL) signal levels. Look at the "Single Sided Serial" Arduino design for the basic circuitry.