  The operator product expansion is used to obtain model-independent
predictions for the first two moments of the renormalized B-meson light-cone
distribution amplitude phi_+(omega,mu), defined with a cutoff omega<Lambda_UV.
The leading hadronic power corrections are given in terms of the parameter
Lambda(bar)=m_B-m_b. From the cutoff dependence of the zeroth moment an
analytical expression for the asymptotic behavior of the distribution amplitude
is derived, which exhibits a negative radiation tail for omega>>mu. By solving
the evolution equation for the distribution amplitude, an integral
representation for phi_+(omega,mu) is obtained in terms an initial function
phi_+(omega,mu_0) defined at a lower renormalization scale. A realistic model
of the B-meson light-cone distribution amplitude is proposed, which satisfies
the moment relations and has the correct asymptotic behavior. This model
provides an estimate for the first inverse moment and the associated parameter
lambda_B.
