I just picked up an older Garmin nuvi 2360 that was onsale this past week for around $140.
It has built-in bluetooth and voice recognition. The voice recognition seems to just wait for you to say the "voice activiation command"....I set mine to repond to "navigation", and it seems like I'm talking to a sci-fi starship.
This seems to be working well, just leave it on while in the car. While driving my "starship", I can just speak out commands, and the navigation picks them up. I do have to press mute on my stereo though--a bit annoying. I think I will go ghetto and use velcro to attach it somewhere--or maybe ducttape the garmin docking piece to the underside of front storage "flippy-thingy". ha! (Actually, it seems to be more consistent with a voice-recognition device than to have to press the button on the steering wheel.)
Anyway, I tried pairing it up with bluetooth, but it seems that the Volt does not want to pair. I guess both devices are only setup to pair with phones and not to each other. Oh well...
If anyone found a clever and useful way to have a garmin with bluetooth and voice recog connect with the Volt, let me know. (And what features are possible?).
Otherwise, I may simply just pair them both up with a spare Andriod phone and work to find some usefull Andriod app to go with the Volt.