  We report the detection of pulsed X-ray emission ($4.9\sigma$) from the
binary millisecond pulsar PSR J0218+4232 in a 100 ks ROSAT HRI observation. The
pulse profile shows a sharp main pulse and an indication for a second weaker
pulse at $\sim$ 0.47 phase separation. The pulsed fraction is 37 \pm 13%. PSR
J0218+4232 was several times in the field of view of the high-energy
$\gamma$-ray telescope EGRET and a source positionally consistent with the
pulsar was detected above 100 MeV. Spatial and timing analyses of EGRET data
indicate that the source is probably multiple: Between 0.1 GeV and 1 GeV PSR
J0218+4232 is the most likely counterpart, while the BL Lac 3C66A is the best
candidate above 1 GeV. If part of the EGRET signal truly belongs to the pulsar,
then this would be the first millisecond $\gamma$-ray pulsar.
