WASHINGTON — Three New York Democrats, including mayoral hopeful Anthony Weiner, are among a small number of congressmen who are formally protesting President Bush's election, The Post has learned. Weiner's signature in support of a highly controversial letter sent yesterday to Vice President Dick Cheney, who serves as president of the Senate, and other congressional leaders comes as a surprise because the other lawmakers are among the most liberal, stridently anti-Bush members of Congress. Weiner, who has a relatively moderate voting record and is now trying to oust Mayor Bloomberg, raised eyebrows by jumping on board because he is not...