  We study the hidden conformal symmetry of the extremal black holes. We
introduce a new set of conformal coordinates to write the $SL(2,R)$ generators.
We find that the Laplacian of the scalar field in many extremal black holes
could be written in terms of the $SL(2,R)$ quadratic Casimir. This suggests
that there exist dual CFT descriptions of these black holes. From the conformal
coordinates, the temperatures of the dual CFTs could be read directly. For the
extremal black hole, the Hawking temperature is vanishing. Correspondingly,
only the left (right) temperature of the dual CFT is non-vanishing and the
excitations of the other sector are suppressed. In the probe limit, we compute
the scattering amplitudes of the scalar off the extremal black holes and find
perfect agreement with the CFT prediction.
