I just found these little video nuggets (one and two) on the NextGen user groups site. If you want to see a demonstration of Windows Vista's speech recognition in action have a watch, they are each 3mins in length. In the first, Richard uses the speech recognition to write text in Notepad, play Solitaire and surf the web. In the second, he uses the speech recognition to drive Microsoft's Visual Studio development tool to write a simple 'Hello World' application. The second video is interesting because it shows the mouse grid technique for zeroing in on the screen element you want to click.
Can someone tell me - can you do this on a Mac?