The first way is using commands in the terminal.... the command is...
sudo apt-get install apache2 mysql-server php5 libapache2-mod-php5 php5-xsl php5-gd php-pear libapache2-mod-auth-mysql php5-mysql
The second way to install is using TASKEL... a TASKEL is a software application tool that groups some packages into tasks and allows the user to install the packages from the task.. u can install it from the terminal by typing...
sudo taskel install lamp-server
Another way of suing the TASKEL is by using the SYNAPTIC PACKAGE MANAGER ... open synaptic package manager from
system->administration->synaptic package manager
then in the edit menu click on mark packages by taskel and from the list select LAMP server and apply.... it installs the lamp server on to ur system!!!