It doesn't yet use units like "turn left in 300 feet." Instead, it would say something like, "Turn left at Graphite Street." You can use the map itself to get a visual indication of how far away the turn actually is. I use the feature more as a reminder (in case I fall asleep at the wheel ).

You will need flite installed, which you can get from my Nokia 770 page by downloading and installing the flite deb. Nothing will break if you don't have it installed - it just won't talk to you as you drive.