  We review the state-of-the-art theoretical analyses of tau decays into a pair
of mesons and a neutrino. The participant vector and scalar form factors,
$f_{+}(s)$ and $f_{0}(s)$, are described in the frame of Chiral Perturbation
Theory with resonances supplemented by dispersion relations, and the physical
parameters of the intermediate resonances produced in the decay are extracted
through the pole position of $f_{+,0}(s)$ in the complex plane. As a side
result, we also determine the low-energy observables associated to the form
factors. We hope our study to be of interest for present and future
experimental analyses of these decays.
