Beat Detection Algorithm can detect the beats of any audio source in realtime by using frequency spectrum analysis (FFT), audio energy or both simultaneously.
DEMO SCENE: http://www.3y3.net/BeatDetection/BeatDetection.html
You can use the script in your games or applications and make your applications react to the music. It is really easy to configure, simply add the script to the object with the audio source and choose the detection mode:
The code is high-performance and you can use it on mobile devices and even use several scripts simultaneously to control many audio sources.
Full source C# code included.