  In this talk we will discuss the low energy dynamics of non-BPS branes
constructed as stable brane/anti-brane pairs at an orbifold. In particular we
will determine the effective field theory and compare its predictions with
those of the full open string theory. While the position and vector degrees of
freedom have the familiar form found in supersymmetric gauge theories, the
massless modes orginating in the tachyonic sector display novel non-commuting
flat directions. We will show that these flat directions persist to al orders
in alpha'. Finally we will briefly report on the open string loop corrections.
