  This paper describes the measurement of collective flow for charged particles
in Au+Au collisions at sqrt{s_NN}} = 130 GeV using the PHOBOS detector at the
Relativistic Heavy Ion Collider (RHIC). An azimuthal anisotropy is observed in
the charged particle hit distribution in the PHOBOS multiplicity detector. This
anisotropy is presented over a wide range of pseudorapidity (eta) for the first
time at this energy. The size of the anisotropy (v_{2}) is thought to probe the
degree of equilibration achieved in these collisions. The result here,averaged
over momenta and particle species, is observed to reach 7% for peripheral
collisions at mid-rapidity, falling off with centrality and increasing |eta|.
Data are presented as a function of centrality for |eta|<1.0 and as a function
of eta, averaged over centrality, in the angular region -5.0<eta<5.3. These
results call into question the common assumption of longitudinal boost
invariance over a large region of rapidity in RHIC collisions.
