Until that happens, I'm not doing it. Also if you download the Google Voice app from the market, regardless of carrier, you have almost every feature. The only one missing is to have GV take over your Sprint number. My VZW has been using my GV number for a year now. (Yes I have both a Sprint Epic and VZW Fascinate)
This article needs to be corrected because now you do not need to port your number to Google Voice. You simply integrate your Sprint phone number into your Google Voice account. There is an option to select your Sprint phone number within Google Voice set up. They were able to port their number before but since the integration of Sprint and Google Voice you keep your Sprint phone number with Sprint and Google voice integrates the number as the google voice number!
I wish Google would at least consider making a bid for T-Mobile once the FCC and Justice tell AT&T no. They could spin it off and operate the two entities separately. We need T-Mobile in the wireless arena.