This is only one way to do it. It's really far easier to install GV by Evan Charlton, rather than use the official Google Voice app. Then you never have to worry about the outgoing number changing (and it will and a lot of people get burned forgetting to check over time.)Remember - in order to have truly incoming AND outgoing free calls you must enter TWO numbers in "friends and family" if you are using the GV application. You must enter your GV number for incoming and the number your GV application dials for outgoing. Once in a while GV will change this outgoing number so you have to pay attention and update your "friends and family" from time to time.