ISwipemusic (free) has the interface alright if you want to set user interface (UI) design back ten years or so. Though the app does blow up text size, this technique merely expands the song titles to fill one line. As a result, tracks with long titles — such classical music or anything by Fall Out Boy — appear just as small as they would in the iPhone’s native iPod player.
The UI also responds extremely slowly or not at all, which negates the safety benefits of larger text as the driver stares blankly at a frozen screen, perhaps even spiking the device onto the passenger seat with a final declaration of “I guess I can listen to Funkytown again.”
Conclusion: Don’t bother with this one.