Google Voice for Android Update
Google have updated their Google Voice for Android app to include “inbox synchronization."
With Google Voice 0.3.2, push-like notification now alert the user to incoming text and voice messages as they arrive. Previously, the app would search for new messages once every fifteen minutes.
The update is available to download from the Android Marketplace.
Please note that you will require a Google Voice account to use the app, and at this time, Google Voice is only available to US customer.