just want to make sure you all know about Beatnik. It's a browser plug-in and they offer an Editor (Mac only, PC due very soon) for importing samples and keymapping them into instruments.
It's alot like a softsynth/sampler but it's highly controllable via scripting, much like Flash. In fact it interfaces really well with Flash. Controll track mutes, volumes, pans, transpose, tempo, and keep them all in sync.Use it for music or for general sonification of a site.

Check out Beatnik.com. I moderate a discussion forum devoted to Flashnik (Flash and Beatnik) and have a few tutorials on my site: http://www.bongdern.com/Flashnik

Okay. Off the soap box for now.

/chris