Late reply here, just noticed an "error" in browsing some older posts.
Mike says the CS3 beta only works for 2 days. My copy is working until sometime in March when the official copy is on sale. Yes, Curvemeister does work in CS3 with no problems.
I did note that, although I prefer viewing images with the gray background, that you must be in "window" mode in CS3 in order to use the Curvemeister window for droppers, etc. No big deal, just changes my workflow a bit.