Ocaml tutorials / resources:

* http://caml.inria.fr

Here are some more specific resources I've found helpful:

* http://caml.inria.fr/pub/docs/oreilly-book/ - English translation of a French O'Reilly book on OCaml, free text online. This is the best English book for learning OCaml, IMHO. It covers a ''lot'' of ground, such as: using OCaml as a functional language, an imperative language, and an OO language, the pros and cons of each approach (and mixing them), debugging/profiling, how garbage collectors work (with OCaml's as a case study), how to use ocamllex and ocamlyacc (and an overview of lexers/parsers in general), concurrency, network programming, etc. -- ScottVokes
* http://flint.cs.yale.edu/cs421/case-for-ml.html - "Why ML/OCaml are good for writing compilers", a concise summary of OCaml's strong points. Ten years old (!), but still seems pretty accurate.
* http://enfranchisedmind.com/blog/posts/why-ocaml-sucks/ - Similarly, a summary of OCaml's weak points. (Particularly #7!)