Serial Input to control Actuators

I am fairly new to programming, and using Micro controllers. I have more experience with the HCS12 Freescale board, but this board is far to expensive to use in this project I must complete. So i apologize if my questions are not very detailed, since I do not know much about this.

I am sending a signal out the serial port of my computer from a car simulation game which sends 3 output signals to the serial port. I am trying to figure out how I can make these inputs into the arduino Uno. These values will be changing constantly and I need the arduino to calculate values with them in order to extend actuators a certain distance.

If I cannot get the values from the car simulation game I plan on making three simple sliders in visual basic to "simulate" the inputs I need, in this case how would I get these values to the arduino Uno board? I have never interfaced two different programming programs together.

So my main question is how can I get these values to the Arduino Environment, or from the serial port to the Arduino board.

Any help would be appreciated, Thanks!!

I am sending a signal out the serial port of my computer

One does not send signals to the serial port. One sends data to the serial port.

I am trying to figure out how I can make these inputs into the arduino Uno.

Depends on whether you are actually sending data to the serial port or to the USB device masquerading as a serial port.

If it's the latter, the Arduino has this neat class called - wait for it - you'll be amazed - Serial, for reading and writing serial data to/from the "serial port".

These values will be changing constantly and I need the arduino to calculate values with them in order to extend actuators a certain distance.

You'd be a lot better off calculating the values on the PC which is several orders of magnitude faster, and sending the value to the Arduino.