Google Inc. has acquired a mobile social networking start-up called Zingku Inc., the search company’s latest move to provide more services through mobile phones.

Zingku aims to make it easier for people to share photos, send invitations or conduct polls among friends via mobile phone. It also provides a way for businesses to send “mobile flyers” to customers advertising products and services.

Zingku was started in 2005 and the service has been in testing with a limited number of users in the U.S. New account sign-ups have been frozen following Google’s acquisition, according to Zingku’s Web site. Existing accounts will be transferred to Google unless they are cancelled by Oct. 4.