Use OCaml, it is open source, free and unux friendly. In fact, F# is an adaptation of OCaml for .NET platform.
F#'s compiler is open source.
The language can compile into CIL, javascript, and a handful of other build targets.
"can compile into ... javascript"
I don't believe this is true, at least not easily.
Pit and WebSharper are two examples that can turn F# into JS.
Have you ever noticed that in every post about fp languages there is always a mention about using f#. I've never seen any language-advertisements at this level.
Have you ever noticed that in every post about fp languages there is always a mention about using Haskell. I've never seen any language-advertisements at this level.