Multiple Arduinos connected to one computer using Serial

Me and a friend are working on another part of our quad rotor project now that we got a motor running (thanks to you guys!). We have 2 arduinos, one acts as a control panel, and the other is on the copter. Later, we will use Xbees to do this all wirelessly, but right now we are going to have both devices connectd to the computer. Is there a way to have a program so that when a potentiometer is turned on the control device, it can be read in and used to set a value on the copter device? I have heard that this can be done through a Serial connection but I do not understand how? Thank you, K and E

Just the two Arduinos?

Then connect Rx of one to Tx of the other (eg. pins D0/D1) and ditto for the other way (Tx to Rx). Also connect Gnd. So a total of 3 wires. Note that apart from Gnd, the two other wires swap over.

Then when you transmit on the first the other will receive, and vice-versa. Make sure you use the same baud rate.

You will probably need to disconnect these wires if programming via the bootloader.