  We establish analogs of the Darboux, Moser and Weinstein theorems for
prequantum systems. We show that two prequantum systems on a manifold with
vanishing first cohomology, with symplectic forms defining the same cohomology
class and homotopic to each other within that class, differ only by a
symplectomorphism and a gauge transformation. As an application, we show that
the Bohr-Sommerfeld quantization of prequantum system on a manifold with
trivial first cohomology is independent of the choice of the connection.
