  We parameterize all classical probe brane configurations that preserve 4
supersymmetries in (a) the extremal D1-D5 geometry, (b) the extremal D1-D5-P
geometry, (c) the smooth D1-D5 solutions proposed by Lunin and Mathur and (d)
global $AdS_3 \times S_3 \times T^4/K3$. These configurations consist of D1
branes, D5 branes and bound states of D5 and D1 branes with the property that a
particular Killing vector is tangent to the brane worldvolume at each point. We
show that the supersymmetric sector of the D5 brane worldvolume theory may be
analyzed in an effective 1+1 dimensional framework that places it on the same
footing as D1 branes. In global AdS and the corresponding Lunin-Mathur
solution, the solutions we describe are `bound' to the center of AdS for
generic parameters and cannot escape to infinity. We show that these probes
only exist on the submanifold of moduli space where the background $B_{NS}$
field and theta angle vanish. We quantize these probes in the near horizon
region of the extremal D1-D5 geometry and obtain the theory of long strings
discussed by Seiberg and Witten.
