  We use QCD sum rules to study the recently observed meson $Z^+(4430)$,
considered as a $D^*D_1$ molecule with $J^{P}=0^{-}$. We consider the
contributions of condensates up to dimension eight and work at leading order in
$\alpha_s$. We get $m_Z=(4.40\pm0.10) \GeV$ in a very good agreement with the
experimental value. We also make predictions for the analogous mesons $Z_{s}$
and $Z_{bb}$ considered as $D_s^*D_1$ and $B^*B_1$ molecules respectively. For
$Z_{s}$ we predict $m_{Z_{s}}= (4.70\pm 0.06) {\rm GeV}$, which is above the
$D_s^*D_1$ threshold, indicating that it is probably a very broad state and,
therefore, difficult to be experimentally seen. For $Z_{bb}$ we predict
$m_{Z_{bb}}= (10.74\pm 0.12) {\rm GeV}$, in agreement with quark model
predictions.
