An update has been submitted to Microsoft, which includes numerous bug fixes. This update also addresses the problem that many users have had with the Nokia Lumia 900. Unfortunately this new version will not be available for downloading until the end of next week, due to the current wait times for Marketplace approvals.
MetroTalk is the first Windows Phone app that gives a fluid Google Voice experience. It comes with full Mango support and includes push notifications for instantly receiving SMS messages and voicemail, even when the app is not active. Performance and user experience have been the major focus during development.
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Download here from the Marketplace.