  Quantum computing and quantum communication are remarkable examples of new
information processing technologies that arise from the coherent manipulation
of spins in nanostructures. We review our theoretical proposal for using
electron spins in quantum-confined nanostructures as qubits. We present single-
and two-qubit gate mechanisms in laterally as well as vertically coupled
quantum dots and discuss the possibility to couple spins in quantum dots via
exchange or superexchange. In addition, we propose a new stationary wave
switch, which allows to perform quantum operations with quantum dots or
spin-1/2 molecules placed on a 1D or 2D lattice.
