Here is the command for the fastest and easiest way to install MySQL,PHP and Apache in Ubuntu Ibex
* Open terminal (Alt+F2 then gnome-terminal) and type
sudo tasksel install lamp-server

Done, just follow the wizard and your ready to go. To check if its okay
http://localhost

If it doest show you “It works” you need to start it. To start the apache
sudo /etc/init.d/apache2 start

These are optional
Enable .htaccess
sudo gedit /etc/apache2/sites-available/default
Change the line 11 (AllowOverride None, under directory /var/www) to AllowOverride All
Save and restart the apache
sudo /etc/init.d/apache2 restart

Enable Mod Rewrite
Open terminal and type
sudo a2enmod rewrite
Restart the apache
sudo /etc/init.d/apache2 restart