Step to get YAL it working

assume YAL is install in /usr/share/nagios-local

this way an upgrade to nagios doesn't affect YAL installation

1) cd to /usr/share

and extract tar file YAL-1.0.tar.gz

NOTE: will create nagios-local directory, if you have one already extract somewhere else
rename it as you like and move ti to /usr/share

2) cp /usr/share/nagios-local/YAL/lcd.cgi to your cgi-bin

and modify it to reflect banner menu etc..

3) modify /usr/share/nagios-local/banner.htm to point to lcd.cgi

4) enable SSI in your server

5) e.g. Apache server I've for /usr/share/nagios-local Directory block

        <Directory "/usr/share/nagios-local">
        Options Includes
        XBitHack on
        .... 

6) chmod +x /usr/share/nagios-local/banner.htm

7) you have to enable Index handler for .htm files as YAL files are ending as .htm

I've

               DirectoryIndex index.htm index.html index.html.var 

8) Modify /etc/nagios/cgi.cfg

         physical_html_path=/usr/share/nagios-local

9) in Apache conf file for your nagios, modify

        Alias /nagios "/usr/share/nagios-local"
        <Directory "/usr/share/nagios-local">

10) finaly copy /usr/share/nagios-local/YAL/ledmarquee.gif your HTML document root

11) Restart apache/httpd

12) to make your own banner/side menu, following files has to be modified

12.1) /usr/share/nagios-local/banner.htm

12.2) /usr/share/nagios-local/middle.htm

12.3) /usr/share/nagios-local/side/dtree.css

12.4) /usr/share/nagios-local/side/dtree.js

12.5) /usr/share/nagios-local/side/dtree_data.js

12.6) /usr/share/nagios-local/images/diglinks_*

NOTE: dTree package is from www.destroydrop.com/javascript/tree/ inca case you would like to update the one comes with YAL