> a point of law : i developped a tool generating documentation from OCaml
> code ; this tool is linked with some modules of the OCaml distribution.
> What kind of license is needed to make this tool freely available on ze
> net ?

It depends which part of the OCaml distribution you're linking with:
the standard libraries and runtime system (LGPL licence) or the
compiler proper (QPL license).

Assuming for instance that you're linking with some compiler modules,
the QPL asks you to make the source code of your application available
at no charge, and to allow users to redistribute sources or binaries
at no charge either.  Any open source license will guarantee this.

Moreover, if you made modifications to some OCaml source files, the
QPL asks that you distribute them "in a form that is separate from
[OCaml]", e.g. as patches.  This clause is a bit fuzzy, but a simple,
safe way to comply is to distribute just your own sources (the files
you wrote from scratch, plus diffs for the modified OCaml source files if
any), then instruct users to fetch the OCaml sources and extract the
parts your program needs.  The latter can be automated as a Makefile
entry.

For the parts covered by the LGPL, it's harder to see the exact
limitations imposed by the LGPL (it's a long, wordy document), but
everything should be OK if you distribute your application under the
LGPL, the GPL, or any "more free" license (X11, BSD without
advertising clause, etc).

Hope this helps.

- Xavier Leroy