Using the Kuznetsov trace formula, we prove a spectral decomposition for the
sums of generalized Dirichlet L-functions. Among applications are an explicit
formula relating norms of prime geodesics to moments of symmetric square
L-functions and an asymptotic expansion for the average of central values of
generalized Dirichlet L-functions.Comment: to appear in Revista Matem\'atica Iberoamerican