Welcome to the icinga package for Debian GNU/Linux!
Below are some debian-specific notes which may be of help to you.

If you have questions about using/configuring nagios, you should probably
contact the nagios-users mailing list and NOT the maintainers:

	nagios-users@lists.sourceforge.net

Of course we'd be happy to hear about any bugs you find, and are always
open to discussing any ideas you might have for improvement.  you can
contact the debian icinga maintainers at:

	pkg-nagios-devel@lists.alioth.debian.org

External Commands
^^^^^^^^^^^^^^^^^
Icinga is not configured to look for external commands in the
default configuration as a security feature. To enable external
commands, you need to allow the web server write access to the
nagios command pipe.  the simplest way of doing this is to
set check_external_commands=1 in your Icinga configuration,
and then change the permissions in a way which will be maintained
across package upgrades (otherwise dpkg will overwrite your
permission changes).  The following is the recommended approach:

- activate external command checks in the Icinga configuration. this
  can be done by setting check_external_commands=1 in the file
  /etc/icinga/icinga.cfg. 

- perform the following commands to change directory permissions and
  to make the changes permanent:

/etc/init.d/icinga stop
dpkg-statoverride --update --add nagios www-data 2710 /var/lib/icinga/rw
dpkg-statoverride --update --add nagios nagios 751 /var/lib/icinga
/etc/init.d/icinga start

Manually Providing / Overriding Authentication Configuration
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The default debian configuration for icinga+apache is to use
an htpasswd style file in /etc/icinga/htpasswd.users.  if you
choose not to (or otherwise didn't) provide a password during package
configuration, we assume that you know what you're doing and will
not get in your way.  however, if you don't know what you're doing,
you should either dpkg-reconfigure icinga-common and provide
a password, or read the fine manual for htpasswd(1).