  We show how shared entanglement, together with classical communication and
local quantum operations, can be used to perform an arbitrary collective
quantum operation upon N spatially-separated qubits. A simple
teleportation-based protocol for achieving this, which requires 2(N-1) ebits of
shared, bipartite entanglement and 4(N-1) classical bits, is proposed. In terms
of the total required entanglement, this protocol is shown to be optimal for
even N in both the asymptotic limit and for `one-shot' applications.
