  We study the temperature-dependent conductivity $\sigma(T)$ and spin
susceptibility $\chi(T)$ of the two-dimensional disordered Hubbard model.
Calculations of the current-current correlation function using the Determinant
Quantum Monte Carlo method show that repulsion between electrons can
significantly enhance the conductivity, and at low temperatures change the sign
of $d\sigma/dT$ from positive (insulating behavior) to negative (conducting
behavior). This result suggests the possibility of a metallic phase, and
consequently a metal-insulator transition,in a two-dimensional microscopic
model containing both interactions and disorder. The metallic phase is a
non-Fermi liquid with local moments as deduced from a Curie-like temperature
dependence of $\chi(T)$.
