How to Get a GameBoy Advance Emulator on an iPhone

1. Launch the Cydia app store on your jailbroken iPhone by tapping its icon on the home screen.

2. Tap the 'Search' button in the menu at the bottom of the screen and type 'gpSPhone' into the search bar at the top. As of the date of publication, this is the only GameBoy Advance emulator available for the iPhone.

3. Tap the entry for the gpSPhone app in the search results, followed by the 'Install' button. Tap the 'Confirm' button on the next screen to download and install gpSPhone on your iPhone.

4. Download and install the free iPhone Explorer application on your computer. This software allows you to browse the iPhone's files and folders as if it were a typical USB mass storage device.

5. Connect the iPhone to your computer using its USB cable. Click the iPhone Explorer icon in 'My Computer' if you're using a Windows PC, or the icon on the desktop if you're using a Mac. This icon is automatically provided by the iPhone Explorer software when it detects that a jailbroken iPhone has been connected.

6. Navigate to the '/private/var/root/Media/ROMs/' folder in iPhone Explorer. Drag and drop your GameBoy Advance game ROMs into this folder.

7. Disconnect the iPhone once file transfer is complete, and launch the GameBoy Advance emulator by tapping its icon on the home screen.