WASHINGTON — A powerful new lobbying force is coming to town: Barack Obama's triumphant army of 3.1 million Internet-linked donors and volunteers. In a mass e-mail thanking them, written moments before his Grant Park victory speech, Obama put them on notice. "We have a lot to do to get our country back on track, and I'll be in touch soon about what comes next," he wrote. Many are eager. "I'm going to be sitting at the phone, asking, 'What do you want me to do next? I'm ready,' " said volunteer Courtney Hood, 37, a mother of three from Owings,...