With the proliferation of mobile devices and PDAs loaded with fully-functional web browsers, Moodle has had to keep up with the times. There is a Moodle for Mobile that can be used with basic mobile phones and PDAs, but this lacks graphical elements and is therefore rather difficult to use.
There is also an Orangewhitepda theme that comes with the standard release of Moodle that can be used for mobile devices. This is a low-graphics, large-text theme that again can be customized fully to meet your requirements. The options here are to build a whole Moodle site specifically for mobile devices by using this theme, or to have a link somewhere on the front page of Moodle that loads this theme. To do this, you would need to use session themes, so that a particular theme is loaded for the users based upon the session.
To do this, two things need to be done. Firstly, you will need to add the following PHP code to the config.php file in the root of your Moodle installation folder. That's right—not the other one in the root of your theme's folder.
$CFG->allowthemechangeonurl = true;
The config.php file is located at: C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\config.php.
Once you have done this, you can then create a link to your Moodle for Mobile theme somewhere on your home page. When clicked, Moodle would load the orangewhitepda theme only for that session.