  We study the effect of electron-electron interaction on a two dimensional
(2D) disordered lattice. For the case of two electrons the analytical estimates
are presented showing a transition from localized to delocalized states in a
way similar to the Anderson transition in 3D. The localized phase corresponds
to large values of the parameter r_s, which is determined by the ratio of the
Coulomb and Fermi energies. The numerical investigations of the spectral
statistics P(s) in a system with up to N_p=30 spin polarized electrons show the
transition from the Poisson to the Wigner-Dyson distribution at a total
electron energy independent of N_p. The relation to experiments on the
metal-insulator transition in 2D is also discussed.
