[kolis]

We actually analyze the mp3, no need for Winamp DSP at this stage. WE need DSP to mix chords to song, so you hear exact place.

we are working on some web based application, down side is that you have to be connected.

[10ren]

Cool. I was thinking you sell both a webapp (free trial + normal price) and download (super-premium price!).

Uh... why don't you make your own webapp player? For the download version, you could setup a server on the user's computer, thus reusing the same server and client code (but the user doesn't have to be connected).