Maybe you should experiment with Wink. It's freeware and generates Flash animations. I don't know if it supports sound, but the sound quality on the dotlrn demonstration on angelfire was pretty bad anyways, and by using sound you're excluding people that are deaf.
I know Wink does support explanation ballons, which I find more captivating anyways.
http://www.debugmode.com/wink/
-Roberto
