Cool! ...For a Beta ;)
That was damn cool! I've seen a few others that have tried (and failed) to do what you just accomplished. The flash is very clean and well-put together- graphics, sound, style, etc. Different from DDR style games in that you have to hit the PGDN key- tho it's more realistic to how you play an actual guitar since you position your fingers on the frets beforehand anyway.
It looks like you put in a good deal of effort and thinking into the project. 'Grats and I look forward to the first version! :)