Until we have the documentation ready, here is a simple overview.  The
compiler supports compiling multiple javascript source files together (so
they are renamed and optimized as a unit) but the output divided into
"modules" that can be loaded separately.  The idea is that core
functionality can be part of the initial module that is initially loaded and
less used features can be loaded later.

Here is an example:

  java -jar compiler.jar --js src1.js --js src2.js  --js src3.js --module
first:2 --module second:1:first

This will create to modules:
  first.js
  second.js

The first module, I've named "first", contains the 2 file (the first two
--js parameters listed).  The second module, I've named "second", contains
one file, the next --js entry following those included in the first module,
the second module depends on the first.

"--module_output_path_prefix" is straightforward.

"--module_wrapper" is simply a way to add some extra text before and or
after the compiler output.  For example, if you wanted to add a comment to
the top of the file:

--module_wrapper "/* copyright 2010 */ %s"

Have fun.

-John