We study the distribution P(σ) of the equivalent conductance σ for Erdös-Rényi (ER) and scale-free (SF) weighted resistor networks with N nodes. Each link has conductance g e-ax, where x is a random number taken from a uniform distribution between 0 and 1 and the parameter a represents the strength of the disorder. We provide an iterative fast algorithm to obtain P(σ) and compare it with the traditional algorithm of solving Kirchhoff equations. We find, both analytically and numerically, that P(σ) for ER networks exhibits two regimes: (i) A low conductance regime for σ< e-a pc, where pc = 1k is the critical percolation threshold of the network and k is the average degree of the network. In this regime P(σ) is independent of N and follows the power law P(σ)∼ σ-α, where α=1-ka. (ii) A high conductance regime for σ> e-a pc in which we find that P(σ) has strong N dependence and scales as P(σ)∼f(σ,a pc N3). For SF networks with degree distribution P(k)∼ k-λ, kmin ≤k≤ kmax, we find numerically also two regimes, similar to those found for ER networks.