The USGS in partnership with the University of Utah produces the Yellowstone Volcano Observatory. The Yellowstone Volcano Observatory records and publishes data about volcanic activity in Yellowstone National Park. Much of the material on the site is very scientific in nature, but the Observatory website does offer some educational materials accessible to the non-scientist. The Yellowstone Volcano Observatory offers three videos about the volcanoes of Yellowstone. The Observatory also offers photographic tours of Yellowstone.

Some other good resources for learning about Yellowstone National Park can be found in Google Earth. Turn on the National Geographic and Streetview layers to some excellent images from within the park.

Applications for Education
Yellowstone National Park is known for its natural wonders. The Yellowstone Volcano Observatory provides some resources for high school science teachers to use in teaching about the geology of Yellowstone.

Here are some related items that may be of interest to you:
Tour Mount Redoubt in Google Earth
Forces of Nature – Earth Science Resources
Five Resources for Teaching About Earthquakes