<p>F# is derived from OCaml, but what major items are missing or added? Specifically I'm curious as to whether the resources available for learning OCaml are also useful to someone who wants to learn F#.</p>

F# supports OCaml syntax directly.  It might not be 100% compatible, but I think it's pretty close.
http://plus.kaist.ac.kr/~shoh/fsharp/html/index.html
Here is a list of differences (not sure how up-to-date it is)
http://plus.kaist.ac.kr/~shoh/fsharp/html/fsharp-vs-ocaml.html