  The creation, coherent manipulation, and measurement of spins in
nanostructures open up completely new possibilities for electronics and
information processing, among them quantum computing and quantum communication.
We review our theoretical proposal for using electron spins in quantum dots as
quantum bits. 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 superexchange. We further present the recently
proposed schemes for using a single quantum dot as spin-filter and spin
read-out/memory device.
