We present a simple tight-binding model for the two-dimensional energy bands of polyacene field-effect transistors and for the coupling of these bands to lattice vibrations of their host molecular crystal. We argue that the strongest electron-phonon interactions in these systems originate from the dependence of intermolecule hopping amplitudes on collective molecular motion, and introduce a generalized Su-Schrieffer-Heeger model and is parameter-free once the band mass has been specified. We compute alpha(2)F(omega) as a function of two-dimensional hole density, and are able to explain the onset of superconductivity near 2D carrier density n(2D) approximately 10(14) cm(-2), observed in recent experiments.