If the data is on a remote server (for example, PHP running on a web server, talking to a MySQL server) then you do this in an AIR application the same way you would do it with any Flex application (or ajax application, if you're building your AIR app in HTML/JS).
That's a broad answer, but in fact there are lots of ways to communicate between Flex and PHP. The most common and best in most cases is to use AMFPHP (http://amfphp.org/) or the new ZEND AMF support in the Zend Framework.
This page is a good starting point for learning about Flex and PHP communication:
Also, in Flash Builder 4 they've added a lot of remote-data-connection functionality, including a lot that's designed for PHP. Take a look at the Flash Builder 4 public beta for more on that: http://labs.adobe.com/technologies/flashbuilder4/
Thanks Paul Robertson for your reply. Iam new to adobe air, i need a tutorial where i can learn how to develop a desktop application which gets the data from the web server and stores it in the local machine on application initialization. Then the data in the local machine can be updated,deleted,created locally and finally can be taken back to the remote database on completion through my PHP application.
Flash Builder 4 has introduced a new workflow Data Centric Development.
This makes connection to php , coldfusion and HTTP service very easy.
Check out more about it at http://sujitreddyg.wordpress.com/flash-builder-4/ and Building a database based app using Flex and PHP with Flash Builder 4
Flash Builder 4 beta is at location http://labs.adobe.com/technologies/flashbuilder4/
I have similar issue regarding to getting data from web server to local machine using HTML/JS.
Could you please inform me about the solution? I've been searched and found nothing.