Here is a very good multi-part tutorial on the ins and outs of mobile client / server development, that adds some quite useful functionality on Android, Apple IOS and Blackberry mobile devices.
In this Test Drive, you are going to create a Flex mobile application that retrieves, displays, and modifies database records (see Figure 1). A Flex application does not connect directly to a remote database. Instead, you connect it to a data service written in your favorite web language (PHP, ColdFusion, Java, or any other server-side technology). You will build the front-end Flex mobile application; the database and the server-side code to manipulate database records is provided for you as a PHP class, a ColdFusion component, or Java classes.