The company did not disclose a purchase price.
Fremont, Calif.-based GrandCentral's services let users personalize phone usage with Web-based features like the ability to assign a single phone number that rings various phones at once, records calls and accesses visual voicemail.
The company began beta testing in September 2006. It was founded by Craig Walker and Vincent Paquet, formerly the chief executive and vice president of business development and marketing, respectively, for VoIP company Dialpad Communications Inc. Google competitor Yahoo Inc. bought Dialpad in June 2005 for an undisclosed amount.
"We think GrandCentral's technology fits well into Google's efforts to provide services that enhance the collaborative exchange of information between our users," Google product manager Wesley Chan wrote in a post on the company's blog.
Over on GrandCentral's Web site, the company affirmed Google's acquisition and wrote that the search company will keep beta testing GrandCentral's service.
"Grand Central will remain operational, as will the site, while we integrate with Google. Google will continue to support uninterrupted service for all current GrandCentral customers," the company wrote.
Spokespeople could not be immediately reached at GrandCentral or Google.