@hornartist - thanks! That's very helpful and I understand now. I tested a few calls and it works as you describe. Google Voice is even cooler than I thought. This might be my favorite Google app ever.

The only thing that I still have not tried is making a call FROM my N810 to a regular phone using DialCentral.

I can do this easily with the Skype client on the N810. I'll try DialCentral and see how that works.