If you want your students to engage in Digital Storytelling using multimedia try Memograph. Create a free account, add images, record your voice or add an YouTube video to complete your story or presentation. It is very simple to use and would be great alternative to traditional powerpoint presentations, plus the students can post his/her presentation to a blog/wiki. Try it out for free but if you if would like the no ad version they have educational pricing. I also like that you can easily share the content in a variety of ways.
Here is an example that was posted on the site: