  The critical temperature for the attractive Hubbard model on a square lattice
is determined from the analysis of two independent quantities, the helicity
modulus, $\rho_s$, and the pairing correlation function, $P_s$. These
quantities have been calculated through Quantum Monte Carlo simulations for
lattices up to $18\times 18$, and for several densities, in the
intermediate-coupling regime. Imposing the universal-jump condition for an
accurately calculated $\rho_s$, together with thorough finite-size scaling
analyses (in the spirit of the phenomenological renormalization group) of
$P_s$, suggests that $T_c$ is considerably higher than hitherto assumed.
