
Learn how to get a free, unlimited teacher account and all-access pass for your students here. (Get step-by-step directions and advice here.) Animoto is simple to use, which allows the focus of creation to be educational rather than technical. It has an instant cool factor, but in our school district it has become an important learning tool and very much more than just something "cool". The most common use is as a vocabulary study tool. See a student example made by one of 7th grade teacher Jessica Powell's students here.
Sixth grade teacher Shelly Goodwin uses it like so: She created a private Google Group for her students. Shelly assigns each student a vocabulary word, and s/he chooses pictures from the Internet that represent the word, adds text to announce and define it, then chooses music that goes with the idea. After students finish their Animotos (no more than 30 seconds, she says!), they post the links to a page in their Google Group. Students view classmates' Animotos to study for the test. As a result of this change, vocabulary test scores have skyrocketed (98% pass rate), and students actually remember the words weeks later.
Third grade teacher Laurie Baus used Animoto to help her students learn about the planets. She worried at first they were not going to be able to accomplish the technical tasks necessary, but after half a day, her worries were over. I visited her class one day to find only the sound of clicking and occasional hushed conversation over the light sound of textbook pages being turned. Every child was engaged and involved in learning. After she saw what they'd created, she posted, "I am so proud I could just POP! :-)" on our teacher discussion board.
Animoto is far from the only educational tool that is simply blowing us away, but it is the one our teachers have chosen to implement most broadly. Glogster is another tool that is growing in popularity by the second. I guess the best way to describe it is as an online poster creation tool with music. You'll have to see it to completely understand.

Thanks for allowing me to contribute, Richard! --Amy