  The four six-dimensional ``little string'' theories are all described in the
infinite momentum frame (IMF) as matrix theories by non-trivial 1+1 dimensional
infra-red fixed points. We characterize these fixed points using supergravity.
Starting from the matrix theory definition of M5-branes, we derive an
associated dual supergravity description of the fixed point theories, arising
as the near horizon geometry of certain brane configurations. These
supergravity solutions are all smooth, and involve three dimensional Anti-de
Sitter space AdS_3. They therefore provide a complete description of the fixed
point theories, and hence the IMF little string theories, if the AdS/CFT
correspondence holds.
