My wife and I have been using it. . . more for showing off the capabilities to our friends than for any other reason.
It is very simple to get started--just push the voice button on the steering wheel (right side, center button) and then you get a chime: At that point say "Voice Help" and it will tell you how to say the voice commands.
There is also "Radio Help", "Navigation Help", "System Help", and some others.
For example, you can press the button and say "Radio XM" and it repeats back to you and changes the radio to XM (or FM or AM, etc).
The looks on people's faces who have never used voice recognition is amazing!
As for addresses, after you put in an address (like your own home address), you can "Voice tag" it with something like "Home" and later when you are away, you can press the steering wheel voice button and say "Navigation go to home" and it starts the map guidance feature to take you home.