Hey Blackknight..
funny you should mention this.. I do have the formulae for what you want. Even works out fuel consumption. BUT they are not entirely accurate, usually 0.5 to 1 knot out, and plus or minus one degrees.
the formulae approximate a good old whiz wheel.. but I never bothered to tweak it. I only used it as a check. (I need to model the speed circles on the wheel, the formulae use trig to figure out the soltion)
I can download you the program I created on my mathematical calculator if you want it, or at least provide a more detailed explanation if you want it via email.