  Simultaneous two-dimensional trapping of neutral dipolar molecules in low-
and high-field seeking states is analyzed. A trapping potential of the order of
20 mK can be produced for molecules like ND3 with time-dependent electric
fields. The analysis is in agreement with an experiment where slow molecules
with longitudinal velocities of the order of 20 m/s are guided between four 50
cm long rods driven by an alternating electric potential at a frequency of a
few kHz.
