Sen. Edward M. Kennedy told a cheering Democratic National Convention Monday night that this is "a season of hope" for a stronger future in America, his wave familiar, his voice firm, despite his struggle against brain cancer. And he added: "I pledge to you that I will be there next January on the floor of the United States Senate." "The work begins anew, the hope rises again and the dream lives on," Kennedy said after his seven minutes at the microphone, minutes of high and unexpected drama for delegates waving thousands of Kennedy signs, cheering as he came and as he stepped away into the arms of his wife Vicki. "My fellow Democrats, my fellow Americans, it is so wonderful to be here," he said. "And nothing, nothing is going to keep me away from this special gathering."