Well there are several stuff you need to do in order to start developing php applications.

This is the necessary software for php on Ubuntu:

1. php5 engine
2. apache2 server
3. mysql database server
4. phpMyAdmin and MySQL Workbench. 

I am using the separated installation of the software because I think it is easiest to manage. How ever you can use the xampp installation for linux. It will install everything in one go. Here is the page  xampp.

Ok. So now open terminal on linux and type this command:

sudo apt-get install php5 apache2 mysql-server phpmyadmin

and enter your linux user password.

This will install all 4 parts of the above software except MySQL WB which we will install manually. I will use MySQL WB in my posts because it supports some things phpMyAdmin doesn't. But that doesn't mean that phpMyAdmin is bad. It is browser based database admin tool so some thins are not supported like MySQL WB desktop environment.

 Ok so now we will install MySQL WB. Got to this page http://wb.mysql.com/ adn click download. It will redirect you to the downloads page. Go down and choose the Operating System version. In our case it will be Ubuntu Linux. Select the 32 or 64 bit version and click download. If you already have mysql account log in and select a mirror (choose the nearest one to your location). If not create new one and than download.