Version 1.2 released with Arduino 1.0 support. Thanks PaulDriver for the patch!
I also have a library (toneAC) that does "AC" to drive a speaker at almost twice the volume as the standard tone library. This is possible because I alternate the 5 volts between two pins. In my case, it's designed to be extremely fast, so I use the Arduino's PWM pins and timer 1. This also allows for perfect switching between the two pins without any programming slowing things down.As a bonus, my library can also drive a bicolor two pin LED as yours does (one of my example sketches included with the library controls a bicolor LED with a pot to adjust the cycle speed). You may want to check out my source. As toneAC is designed for ultra speed and accuracy, you must use the timer 1 controlled PWM pins. It also is totally driven totally by port registers for the fastest and smallest code. Looking at my library may assist you. I also have a NewTone library thats a modified version of toneAC but allows you to specify what pin you want to drive a speaker with. This also may assist you with your library.While writing library using port registers and timers may be a little more challenging at first, it's really not that hard once you do it a few times. And, the benefits are many. Very small code size, very fast, color switching and duty cycle can all be done in the background, no reason for delay statements which can kill a project, etc.Best of luck with your project!Tim