We find supertubes with arbitrary (and not necessarily planar) cross section;
the stability against the D2-brane tension is due to a compensation by the
local momentum generated by Born-Infeld fields. Stability against long-range
supergravity forces is also established. We find the corresponding solutions of
the infinite-N M(atrix) model. The supersymmetric D2/anti-D2 system is a
special case of the general supertube, and we show that there are no
open-string tachyons in this system via a computation of the open-string
one-loop vacuum energy.Comment: 1+23 pages, 2 figures, LaTeX. V2, 1+28 pages: Further generalization
to non-planar cross-sections and addition of an entirely new section with the
explicit supergravity solutions. V3, 1+30 pages: Bound on the angular
momentum added, other minor changes in Section