To complete my degree at the University of Hartford, I wrote this simple VST plugin to create a tremolo effect on any audio passed through it. Steinberg made writing VST plugins very easy with thier software developers kit and you can read my tutorials on how to create this plugin here, or read a general walk-through of the SDK example here.
To install the plugin below, simply download the .ZIP file and unzip it into your plugins directory. For most Steinberg Windows applications, this folder is C:\ Program Files\Steinberg\VSTPlugins. You an also use the plugin with any application that accepts the VST standard.