DUBAI (Reuters) - Osama bin Laden has urged militants to concentrate their attacks on Iraqi and Gulf oil facilities, saying it was the most powerful weapon against America, said a transcript of a tape played on the Internet. "Weakening America in Iraq economically, morally and through loss of life is a golden and unique opportunity that you should not waste so not to have remorse," said the tape. The transcript was seen on Friday after the tape was posted on the Internet on Thursday. "The main driving reason behind the enemy's hegemony over our countries is to steal our...