Free calls using Facebook is the promise from Truphone's latest application.

The "call me" option, which Facebook users can opt to download, will allow them to make calls over the Internet.

The call button is moveable and can be placed on Facebook profile pages, dropped into messages as well as forums and wall posts - in fact anywhere in Facebook that accepts attachments.

Truphone adds that the "call me" will only be visible to user's friends and the actual phone numbers will not be revealed.

The application is available to all Facebook users, and neither a Truphone account or special telephone are needed.

Best of all - all calls will be free until 31 December...