From ModMyiFone - Wiki
This is a guide on how to add rogue sources to Installer for your iPhone or iPod Touch.
Adding these sources will give you a greater array of apps and themes to customize your device.
Step 1
- Open up Installer.app. Make sure you have the latest version of 3.0b8
- Select the Sources tab
- Click the "Edit" button
Step 2
Step 3
- Type in the full URL of the source you want to add, including the "http://" For instance, if you're installing the official ModMyiFone.com source, it is http://modmyifone.com/installer.xml (careful on the case sensitivity there, the iPhone likes to capitalize .XML, but it shouldn't be capitalized).
- Click OK
Step 4
- Wait while Installer loads the new source.
Step 5
Step 6
- Close Installer by pressing the Home button.
- Open Installer again and the source you added will now have a name and you can access it's files.
NOTE: Images by CyberGreg and Poeticfolly.