“Together, we will change this country and change the world": This was Barack Obama’s rallying cry to Americans in the closing days of a campaign which saw him become the first black President of the United States.

Barack Obama's newly-minted vice presidential candidate turned his campaign debut into a scathing attack on Republicans seeking four more years in the White House.

Barack Obama introduced Senator Joe Biden of Delaware as his Democratic running mate today before a cheering crowd of thousands, hailing him as a “leader who is ready to step in and be president”.

Barack Obama has picked Senator Joe Biden of Delaware as his US vice presidential running mate, a Democratic party official said today.