A collection of excellent free resources for demonstrating the various circle theorems:
Tim Devereux has created GeoGebra applets which allow exploration of the circle theorems. You can access each theorem from the menu on the left which includes a useful summary of all the theorems.
GeoGebra – Circle Theorems
See also these excellent demonstrations or try the following from Suffolk Maths.
Class Clips – BBC Learning Zone
All Secondary (11-18) Mathematics Clips
For a selection of short videos for the Mathematics Classroom try the Class Clips from BBC Learning Zone. Choose Primary (5-11) or Secondary (11-18) a subject and a topic. Note that each video has several keywords making searching possible.