Google has announced mobile apps for its "Voice" VoIP services, in a move that must have the big players in the market eyeing the new service ever more cautiously.

At present, Google now offers a mobile app for Blackberry phones and Android-powered mobiles, but more platforms will surely be supported in the future as the service is expanded.

Google says: "The mobile application makes using Google Voice with your cell phone simpler by letting you place calls and send SMS messages directly from your Google Voice number".

The video above provides an overview of the service, while there's more info to be had at