This review is based on two lectures given at the 2000 TMR school in Torino.
We discuss two main themes: i) Moyal-type deformations of gauge theories, as
emerging from M-theory and open string theories, and ii) the noncommutative
geometry of finite groups, with the explicit example of Z_2, and its
application to Kaluza-Klein gauge theories on discrete internal spaces.Comment: Based on lectures given at the TMR School on contemporary string
theory and brane physics, Jan 26- Feb 2, 2000, Torino, Italy. To be published
in Class. Quant. Grav. 17 (2000). 3 ref.s added, typos corrected, formula on
exterior product of n left-invariant one-forms corrected, small changes in
the Sect. on integratio