  We discuss the kinetic Sunyaev-Zel'dovich (SZ) contribution to cosmic
microwave background (CMB) temperature fluctuations due to coherent rotational
velocity component of electrons within halos. This effect produces a distinct
dipole-like temperature distribution across the the cluster, and provides a
promising way to measure the angular momentum distribution of gas inside
clusters. Information obtained from such a measurement may provide new insights
to the origin and evolution of angular momentum in hierarchical structure
formation theory. For typical, well relaxed, clusters of mass a few times
10$^{14}$ M$_{\sun}$, the peak fluctuation is of the order a few $\mu$K,
depending on the rotational velocity and the inclination angle of the
rotational axis. For clusters which had underwent a recent merger, the
contribution to temperature fluctuations could be even larger. This dipole
signature is similar to the one produced by lensed CMB towards galaxy clusters,
though the lensing contribution spans a larger angular extent than the one due
to rotational scattering as the former depends on the gradient of the cluster
potential. Since the lensing contribution towards clusters are aligned with the
large scale CMB gradient, when higher resolution observations towards clusters
are combined with a wide field CMB map, these two effects can be separated. An
additional, but less important, source of confusion is the dipolar pattern
produced by the moving-lens effect involving, again, the gradient of the
cluster potential and the transverse velocity. The angular power spectrum of
temperature anisotropies produced by the halo rotation is expected to be
smaller than those due to the thermal SZ and peculiar velocity kinetic SZ
effects.
