How Unix daemons work see:
- general introduction: http://www.enderunix.org/documents/eng/daemon.php
- for handling user/groups:
  http://vmlinux.org/jocke/mirror/cscene.oftheinter.net/www.syclus.com/cscene/CS4/CS4-07.html

Other projects:
- libdaemon (in C): http://0pointer.de/lennart/projects/libdaemon/
- http://www.catb.org/~esr/cookbook/helloserver.c