  The single-particle density of states and the tunneling conductance are
studied for a two-dimensional BCS-like Hamiltonian with a d_{x^2-y^2}-gap and
phase fluctuations. The latter are treated by a classical Monte Carlo
simulation of an XY model. Comparison of our results with recent scanning
tunneling spectra of Bi-based high-T_c cuprates supports the idea that the
pseudogap behavior observed in these experiments can be understood as arising
from phase fluctuations of a d_{x^2-y^2} pairing gap whose amplitude forms on
an energy scale set by T_c^{MF} well above the actual superconducting
transition.
