Flash Movies are showing up all over the Internet.
Visit YouTube and search for Volcanoes and see what comes up:
Mount St. Helens
Great videos show up. Of course, you should preview all YouTube videos before showing in the classroom.
Enlarging to full screen means you can project on your SmartBoard or BigScreen.
Visit THIS PAGE and click on the Flash Movie about Volcanoes that would be fun to use on a SmartBoard. Very Interactive.
CONSIDER THIS: When Teaching Volcanoes, have flash movies running when your students enter the room and also when they are working on volcano-related activities: labs, foldables, worksheets, etc.