I just discovered Windows 7 Speech Recognition (Free with Windows 7) and if you install the Windows Speech Recognition Macros add on (also Free from Microsoft), you can send key presses by voice command.
HOLLY COW!!! I can now call for help by simply saying "Mayday" and it will trigger the necessary key presses to activate the comms command "Anyone Help Me". This is fantastic, I can now use the 'voice radio commands' actually with my voice.
Windows 7 Speech Recognition actually has some terrific ability to recognize and correctly interpret the words you say. Particularly if you take the time to train it.
If you haven't tried this, I would highly recommend it. This is AWESOME!