Today voice messaging company SayNow announced in a blog post it has been acquired by Google. SayNow didn’t disclose much detailed information about the acquisition, but the 2005-founded start-up is expected to announce more details within the near future.

“With an eye to the future, SayNow built a hosted, standards-based platform and a series of applications, which over 15 million users and thousands of celebrities and brands use today.”

The Palo Alto-based SayNow recently raised $7.5 million in funding from Shasta Ventures, Tugboat Ventures, and Altos Ventures. The company’s service is free, but its technology and 15 million users provide a very handsome integration to Google Voice.

Coinciding with the SayNow news, Google today announced the new Number Porting feature for Google Voice.  This enables users to choose a mobile number to be their Google Voice number, and call phones as well as other computers. The add-on feature is available immediately for $20, and the Number Porting of a Google Voice account is reportedly completed within 24 hours. Text message however are enabled after 3 days.

Number Porting is launched after almost two years of expectations aimed towards this previously“…highly requested feature”, but it represents only the latest of voice-related initiatives. Mobile and IP services enable a number of tools and features related to this segment, and we most recently covered voice recognition technology maker Nuance’s launch of Dragon Mobile SDK for Android and  iOS 4.0.