  In this letter we give an overview on recent developments in representation
theory of star product algebras. In particular, we relate the *-representation
theory of *-algebras over rings C = R(i) with an ordered ring R and i^2 = -1 to
the *-representation theory of *-algebras over \mathbb{C} and point out some
properties of the Picard groupoid corresponding to the notion of strong Morita
equivalence. Some Morita invariants are interpreted as arising from actions of
this groupoid.
