  Top quarks produced in pairs are predicted to experience spin correlations.
Due to the large ttbar statistics expected for the LHC, it should be possible
to search for new physics effects in angular variables sensitive to these
correlations. We investigate, for a general two-Higgs Doublet Model (2HDM), the
charged Higgs boson decay of the top quark through the channel $t\to bH^+\to
b\tau^+\nu_\tau$. Analytic results are presented on the spin analyzing
coefficients for this decay mode. We then explore in some detail the
correlation phenomenology in the Type II 2HDM. Finally we present a
hadron-level Monte Carlo analysis, illustrating distributions in azimuthal
angles which are sensitive to correlations in the transverse plane. These
observables are accessible also in the tau channel, and are therefore
particularly interesting for analyzing the $t\to bH^+$ decay.
