According to the Google (GOOG) Voice sign-up page, users now need just one phone number for the service. Previously, users were required to have both a number with a telephone carrier and a second one issued by Google. The search company says that it now offers "a single phone number that rings all your phones." The company adds, "We're excited to announce that you now can get Google Voice with a Google number OR with your existing mobile phone number."
This could be a nightmare for traditional phone companies. The upgrade will allow users to bypass the voicemail features provided by current telephone service providers. It also makes it simple for Google Voice customers to make cheap international calls using the Google infrastructure. The product is not widely available now, but Google says that it will be soon.