Various videos covering all areas of plate tectonics. The videos make excellent starters and plenaries.
http://www.gatm.org.uk/geographyatthemovies/tectonics.html
http://www.teachersdomain.org/collection/k12/sci.ess.earthsys.internal/
http://www.teachersdomain.org/collection/k12/sci.ess.earthsys.surface/
Introduction to plate tectonics:
http://www.teachersdomain.org/asset/ess05_vid_plateintro/
http://www.teachersdomain.org/asset/ess05_vid_wegener2/