I have just created a public repository on bitbucket containing various reusable F# modules that I developed for Asteroid Hunter.
It's all there: https://bitbucket.org/johdex/xnautils/
I had a quick look over the code, it's all pretty clean and short, but it lacks documentation and examples on how to use it.
I ported the code and project files to XNA 4.0 and F# 2.0, but I have not tested the binaries. Chances are, they do not work yet.
Nevertheless, I hope it will be useful to others out here, and help more Xbox games to be written in F#.
UPDATE (Nov 25):
Asteroid Hunter was written for XNA Game Studio 3.1 using F# 18.104.22.168 (from may 2010). As I describe it in further details in the next post, the latest versions of XNA Game Studio and F# are not compatible.