After a year following its favoured, invite-only beta test pattern, Google has made its Google Voice service available to anyone from the United States who wants to sign up for it.

The service is Google’s latest bid to shake up the establishment, and offers a single number that can be applied to existing accounts, be they home, work or mobile, as well as a number of other web-based features. It also offers free national calls and text messages.

In a post on the Google Voice blog by product managers Craig Walker and Vincent Paquet, the firm revealed that it has racked up over one million users of its service in the US since it started inviting consumers to test it.

“A little over a year ago, we released an early preview of Google Voice, our web-based platform for managing your communications,” the post said.  “Today, after lots of testing and tweaking, we’re excited to open up Google Voice to the public, no invitation required.

“Over the past year, we’ve introduced a mobile web app, an integrated voicemail player in Gmail, the ability to use Google Voice with your existing number and more,” the post added, before thanking users for suggesting improvements, including an SMS to email service.