Update 2

After deciding on volcanoes as my topic, I did some research, listing all the helpful websites for kids.  Then, I created a Keynote presentation and shared each slide with iPhoto.  From there, it was easy to use the slides in a Garageband podcast which has a cool volcano tract. 

However, after looking at the science standards, I've decided that knowing the basic types of volcanoes is too basic a concept and not a key science standard.  So, now I plan to use the same applications and process, but I will be revising the content, so that the lesson hits a key standard immediately useful to all the fifth grade teachers.