FlashSpec is a stand-alone application that produces synchronization data specifically for use with Flash. It allows you to control animations and other events in Flash using amplitude or spectrum (frequency) values derived from sound files. It works as a Winamp plugin and thus requires winamp to be installed to work correctly. This allows it to support all audio formats that are supported by winamp, which is a long list. It is a sort of Spectrum analyzer that outputs the values to a textfile that can then be read by flash again.
Software that can be used as an alternative to FlashSpec: