Screenshot of original audio tour experiment.
A partly redone example using Vocaroo:
A couple of thoughts occurred to me:
Audio in Teaching Animations: Mayer and Moreno experimented using animations for teaching. They found that students performed better on tests when they had used animations (such as how a piston works in a car engine) with audio narration rather than with text narration. I strongly suspect that in a Google Earth tour an audio narration will similarly perform better than a text narration for users so this is something we should be doing more of.
Web Services may Change: My experiments with Evoca were free, it would be fine for a student project but if you want something that will last into the future you can't rely on a web service, they may start charging as with evoca. I've experimented this morning with trying to add narration to the web without a web service and the results aren't good. At the moment its still fiddly and requiring techie skill: I used the free and open source Audacity for recording and this tutorial for adding a flash player with sound files. If someone knows an easier way to get audio on the web in little flash applets without using a web service I'm all ears.