If you are doing any kind of PHP development, you'll almost always be using Apache along with it. Here's the quick and easy way to get PHP up and running on your Ubuntu box. First, you'll want to add the extra repositories to Ubuntu's sources.list file. From a command shell, you will run the following commands:

sudo apt-get install apache2 sudo apt-get install php5 sudo apt-get install libapache2-mod-php5 sudo /etc/init.d/apache2 restart

Note that if apache is already installed you can omit the first line. Your web files will now be found in /var/www/