Hi there,
I found a
pretty good tutorial for you. I only glanced over it but i t seems to discuss a lot. One thing I'm not sure it is pointed out in there: Make sure you set the mime type for your sound files correctly, so the browser know what you throw at him.
Regarding search engines, I don't know. So far they mostly ignore these things (except proper alt tags or <noembed> tags). Google and Yahoo have started video and picture search, I have not heard of sound. So use lots of relevant text around the sound, may be even a transcript if the sound contains any lyrics or speech.
Let us know what you experience ends up being.
K<o>