The Joomla! Admin Mobile (JAM!) iPhone application requires a Joomla! plugin to be installed on your site.  First, download the JAM Plugin here.  Remember where you save it.  You will use this in Step 3.

In your Joomla! admin panel, go to Site > Global Configuration > System.
Set Enable Web Services to Yes and Save.

Go to Extensions > Install/Uninstall.  Click the Browse and find the plugin you downloaded in the first step.  Click Upload File & Install to complete the installation of the plugin.

Go to Extensions > Plugin Manager.  Find XML-RPC J Admin Mobile (it may be on page 2).
Click the red X to Enable the plugin.

Make sure you've purchased the J Admin Mobile App from the App Store.
Open JAM! on your iPhone.
A test site will appear in the Sites list.  This will allow you to test that your app is working.
To add a new site, press the + sign in the top right corner.  You will need the following info:

• Host: enter your website address
• Path: enter the path to your xmlrpc index.php. By default, Joomla! uses /xmlrpc/index.php.
• Username: enter the username of an account that is allows to use the JAM plugin. You can configure the access level required by editing the plugin settings. By default, a user must be a Super Administrator.
• Password: enter that password for the account.

That's it!  Have fun!

If you have any issue or questions, contact us on our support forum.