i recall having read about opengrok long time back (
http://www.opensolaris.org/os/projec.../manual/story/) but never really tried it out and it eventually slipped my mind.
thanks to Ocicat for bringing this up. It looks good, i will check it out.
also, groked source code for BSD on the web is a very useful resource. pity freebsd is missing/unknown but i guess one can easily create it on their own computer.