Dunno about the Sprint device you're using, but in Android 2.0 (Droid), in the options section of Voice, you can tell Voice to use your mobile # or Google Voice # to make calls.
Yeap, blind as a friggin' bat! I must have looked at that for at least 10 minutes and didn't see them until I read your post.
I feel like such a tool....
Not sure if I'm having a serious brain cramp or not, but can't find the @ symbol on the qwerty keyboard...or the question mark ( ? )
Am I losing it, or are they there and I'm blind?