I have just updated C68 Player for iPhone to version 1.5.2. This new version includes all songs from the latest YM2149 Archive fro may 29 2010, and many bug-fixes.
And naturally you can now use it as your background music player, with iOS 4 multitasking while jogging or hacking away. Including external controls such as on Apple's earbuds or your iPod compatible car kit.