I've blogged about how to find the Speech APIs on MSDN before, but have you wondered if anybody is writing apps for Speech in Vista? Well ... Yes they are.
One particularly useful app I recently read about was written by Casey Chesnut. He's been into Speech Recognition and Speech technologies for quite a while (I think his first use of SAPI was in 2002 or 2003), and he recently just put together a quick little application that adds some functionality that he wished was included directly in the product, like a configurable hotkey, mouse movement by a specific number of pixels, automatically muting the output when SR is listening, and more...
His calls his extension to Windows Speech Recognition /micBarExtend.
It also sounds like he's up for adding more cool stuff to the app. If you have things you'd like to see him add to extend Windows Speech Recognition, drop him a line.