Software

AnalogX Vocoder - Free multiband standalone vocoder for Windows.
Cylonix - 18-band standalone vocoder for Windows.
Native Instruments Vokator - High-resolution commercial VST plugin and standalone application for Windows and Macintosh. Also has synthesizer functions utilizing fast fourier transformations (FFT).
OrangeVocoder - Realtime commercial VST plugin for Macintosh and Windows. Many examples and demo available for download.
4ormulator Vocoder Extreme - Commercial vocoder for Windows with free demo. Supports more than 500 filters, formant manipulation and LFO control.
Settel Vocoder - 16-band standalone and LADSPA plugin for Linux.
Zerius Vocoder - Free simple standalone vocoder for Windows, Mac and BeOS.