In the past I've used Sound Manager 2.
To be honest, Sound Manager has always been a buggy head ache to me. I've got it to work as a streaming MP3 player before, and once it works it works, but once again I battled Sound Manager today and I decided to look for something new.
That is when I found "Mandy". Mandy uses Jquery to look for events to trigger a sound, and then through some creative DOM manipulation Mandy adds a flash object to your page and plays the sound. I got Mandy to work in one try, as opposed to about 45 minutes with messing with Sound Manager and not getting it to work.
So you might want to give "Mandy" a try.