Advanced Commodore 64 (C64) emulator based on VICE 2.4.3, implements features needed to run the majority of games with additional functionality coming in the future. Works on any device but a 3GS or better is recommended and supports all screen types (including Retina, iPad, & iPhone 5). The source is available under the GPLv3.
Please see the website link for initial setup instructions. Transfer games to your device using SSH or other file transfer method (The recommended location is any directory under /var/mobile/Documents or /var/mobile/Media). Make sure the “mobile” user has write access to the directory for save functionality. If possible use a program that mounts your device over USB like iExplorer (Windows & OSX), or gvfs (Linux) to speed up