Google just unleashed an update to Google Voice, introducing "direct access numbers" in hopes of speeding the process of placing calls. Here's how it's explained on the Google Voice Blog:
Until today, the Google Voice app had to make a request to the Google Voice server every time you wanted to make a call to send us the phone number you wanted to dial. Then the call would be connected via a Google Voice access number. With direct access numbers, we assign a unique phone number to every person you call. This means that we no longer need to use your data network to access the server each time you make a call, so calls will be placed much faster.
Ah, so. All you have to do is update your Google Voice app on your phone, and you should be good to go. (And Google Voice remains a U.S.-only venture for now, sorry, folks.) [Google Voice Blog] Thanks, Nighthawk700!