Donc je veux afficher en local et depuis le net, ma petite page web perso , bon la suite sa viendra plus tard :)
elle ce site ici: /home/tnt/Desktop/www/index.html

celon le totoriel ici:http://doc.ubuntu-fr.org/tutoriel/virtualhosts_avec_apache2_et_dyndns
fichier modifier comme demander (domaine fictif: public) 
=============================================
/etc/host

127.0.0.1	localhost
127.0.1.1	pmch
127.0.0.1	localhost public

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

==============================================
fichier  /etc/apache/site-aviable/defaut :

NameVirtualHost *
<VirtualHost *>
	ServerAdmin webmaster@localhost
	
	DocumentRoot /var/www/
	<Directory />
		Options FollowSymLinks
		AllowOverride None
	</Directory>
	<Directory /var/www/>
		Options Indexes FollowSymLinks MultiViews
		AllowOverride None
		Order deny,allow
		Deny from all
		Allow from localhost
		Allow from 192.168.1.0/24
		# This directive allows us to have apache2's default start page
                # in /apache2-default/, but still have / go to the right place
                RedirectMatch ^/$ /apache2-default/
	</Directory>

	ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
	<Directory "/usr/lib/cgi-bin">
		AllowOverride None
		Options ExecCGI -MultiViews +SymLinksIfOwnerMatch
		Order allow,deny
		Allow from all
	</Directory>

	ErrorLog /var/log/apache2/error.log

	# Possible values include: debug, info, notice, warn, error, crit,
	# alert, emerg.
	LogLevel warn

	CustomLog /var/log/apache2/access.log combined
	ServerSignature On

    Alias /doc/ "/usr/share/doc/"
    <Directory "/usr/share/doc/">
        Options Indexes MultiViews FollowSymLinks
        AllowOverride None
        Order deny,allow
        Deny from all
        Allow from 127.0.0.0/255.0.0.0 ::1/128
    </Directory>


	Alias /private/ /home/tnt/Desktop/www
	<Directory /home/tnt/Desktop/www>
        Options Indexes  FollowSymLinks MultiViews
        AllowOverride All
        Order allow,deny
        Allow from  all
	</Directory>


</VirtualHost>