The classical identification of the predual of B(H) (the algebra of all bounded operators on a Hilbert space H) with the projective operator space tensor product $\overline{H}\widehat{⨂}H$ is extended to the context of Hilbert modules over commutative von Neumann algebras. Each bounded module homomorphism b between Hilbert modules over a general C*-algebra is shown to be completely bounded with $\parallel b{\parallel }_{cb}=\parallel b\parallel$. The so called projective operator tensor product of two operator modules X and Y over an abelian von Neumann algebra C is introduced...