I'm puzzled by the reviews and published specs for the Palm Centro. All of them that I have seen show that voice dialing is not available on the Centro. However, I do have a voice dialing app that came installed on my Verizon Centro. I don't know if it makes a difference but I do have the latest firmware (Centro 1.03-VZW) installed.
I haven't given the voice dial a comprehensive test yet, however the things I haved asked it to do, it has done well, including opening apps and searching my contact list for a particular name.