Generating documentation from Code

In Java there is JavaDoc to generate documentation from comments in source
without making the source unreadable. 
Has someone also thought of using a similar system for kannel as it could
help new developers.
We found that the free CppDoc (http://www.cppdoc.com) does such. I do not
know if it is the best tool available. If someone has experiences with other
(better) tools let me know.
There are a lot of comments in kannel. We wrote some scripts to prepare the
comments so that the tool can recognize them (start comments with /** ...)
and we can get a view on it. This is of course no solution for the whole.
What could be done is to write comments for new/changed code in a way that
API documentation can be generated from it. I would like to do so for parts
that I add or change and provide as patch, but we should agree on that in
advance as it would be an extension to the coding style.

-- 
Andreas W.