Again for MATLAB and adding to Carlos Teixeira's reply, there is World Tides and Currents, by John Boon, with a user-friendly graphical interface. http://www.mathworks.com/matlabcentral/fileexchange/24316-worldtidesworldcurrents2010
Scientists at the Canadian Department of Fisheries and Oceans have produces software that provides a simple graphical-user-interface for tidal predictions. There is a global dataset and several limited-area datasets. The software is based on Java, and should work on any machine. See http://www.bio.gc.ca/science/research-recherche/ocean/webtide/global-mondiale-eng.php