Just for fun, I want to see if I can generate square waves of varying frequencies, and send them to my amp so it can play different notes. I began by stripping an RCA plug, plugging the ground wire into ground, and the signal wire into digital pin 9. Since 9 is a PWM pin on my Duemilanove, I thought i might get some interesting results. I first set it to 100, and got a crisp, relatively high frequency sound. After wiring a pot in to control my PWM value, I noticed PWM makes almost no change. It is now apparent to me that I need to generate my own waves, and use the pot to control the frequency, not the wavelength. I'm relatively new at all of this, so if you do post some sample code or something, I'd greatly appreciate it if it was easy for a newbie like me to follow. Any help, however, would be much appreciated.