A lame duck is an incumbent who has been defeated for reelection, not any outgoing elected official. Therefore, President Bush is no lame duck. This point is important because the constant referrals of him as such has helped to diminish his influence.
A president-elect is one who has been elected president, but not yet taken office. Barak Obama will likely be elected president the first Monday after the second Wednesday (December 15) by the members of the Electoral College. All that has been decided thus far was which Electors have been elected. Therefore, Obama is not yet the president-elect.