Monergism has a very helpful and brief discription of "emergent".
Emerging Churches usually define themselves as those who like to take the life of Jesus as a model way to live, welcome those who are outside, share generously, participate, create, lead without control and function together in spiritual activities or communities who practice the way of Jesus within postmodern cultures. While all of these activities may be good, please notice that all of the above emerging principles are not about what Christ has done for us, but what we do for him. So the the very central core of Christianity is left out. The true gospel, rather, is news about what Christ has already done for us as a Savior, rather than instruction and advice about what we are to do for God. The primacy of His accomplishment, not ours, is the essence of our faith. The gospel of Christ above all brings news, rather than instruction.
Read the entire thing HERE.