Electron spins in semiconductor quantum dots are one of the most
advanced candidates to implement qubits and to eventually realize
quantum information processing in solid-state systems. For this purpose,
they must be proctected against interaction with uncontrolled
"environments" such as phonons, electron reservoirs, or nuclear spins.
With proper control, however, these degrees of freedom can be turned
into a useful resource to enable or enhance quantum computation using
the spin qubits.

We consider two such environments -- the nuclear spin bath and the
surface-acoustic phonons -- and discuss their interaction with the QD
spin, the means to experimentally control them, and potential
applications in quantum information processing.