  We report preliminary results from a study of the charmless exclusive
semileptonic decay B0 -> pi- l+ nu based on the data collected at the
Upsilon(4S) resonance using the BABAR detector at SLAC. The analysis uses
events in which the signal B meson recoils against a B meson that has been
reconstructed in a semileptonic decay B0bar -> D(*)+ l- nubar. We extract the
total branching fraction BF(B0 -> pi- l+ nu) = (1.03 +/- 0.25(stat.) +/-
0.13(syst.)) x 10^-4 and the partial branching fractions in three bins of q^2,
the invariant mass squared of the lepton-neutrino system. From the partial
branching fractions and theoretical predictions for the form factors, we
determine the magnitude of the CKM matrix element |Vub|. We find |Vub| = (3.3
+/- 0.4(stat.) +/- 0.2(syst.) +0.8/-0.4(FF)) x 10^-3, where the last error is
due to normalization of the form factor.
