We propose two potential realizations for quantum bitsbased on nanometre-scale magnetic particles of large spin Sand high-anisotropy molecular clusters. In case (1) thebit-value basis states |0⟩ and |1⟩are the ground and first excited spin states Sz = S and S-1, separated by an energy gap given by the ferromagneticresonance frequency. In case (2), when there issignificant tunnelling through the anisotropy barrier, thequbit states correspond to the symmetric, |0⟩,and antisymmetric, |1⟩, combinations of thetwofold degenerate ground state Sz = ±S. In each casethe temperature of operation must be low compared to the energygap, Δ, between the states |0⟩ and |1⟩. The gap Δ in case (2) can be controlled withan external magnetic field perpendicular to the easy axis ofthe molecular cluster. The states of different molecularclusters and magnetic particles may be entangled by connectingthem by superconducting lines with Josephson switches, leadingto the potential for quantum computing hardware.