  We report results from intensive monitoring of two fields on either side of
M31,emphasizing microlensing involving stars and masses in M31. These results
stem from the three-year VATT/Columbia survey of variability on 3d to 2m
timescales. Observations were conducted intensively from 1997-1999, with
baselines 1995-now,at the Vatican Advanced Technology Telescope, MDM 1.3-meter,
and Isaac Newton telescopes, totaling about 200 epochs. The two fields cover
560 square arcmin total, along the minor axis on either side of M31. Candidate
microlensing events are subject to tests to distinguish microlenses from
variable stars. Fourprobable microlensing events total, compared to carefully
computed event rate and efficiency models, indicate a marginally significant
microlensing activity above expectations for the stellar lenses alone in M31
(and the Galaxy) acting as lenses. Maximum likelihood analyses of the event
distribution in timescale and across the face of M31 indicates a microlensing
dark matter halo fraction consistent with that seen in our Galaxy towards the
LMC (Alcock et al. 2000). For a nearly singular isothermal sphere model, we
find a microlensing halo mass fraction f=0.29 +0.30/-0.13 of total dark matter,
and a poorly constrained lensing component mass 0.02 to 1.5 solar mass, 1 sigma
limits). This study is the prototype for a larger one approaching completion;
between them there is significant evidence for asymmetry in the distribution of
microlensing events across the face of M31, and a large population of halo
microlensing objects. (Abridged)
