There are other Super 8 apps on the App Store but Levi's iSupr8 Film app probably does the best at capture the finicky flickery flippity of those Super 8 cams of yore. Best of all, it's free with new features.
Just updated to include some Levi's-specific features like a denim-esque camera case and other more useful options like adjustable frame rates, customizable film stock (tweak scratches and vignettes), and more—it's probably one of the most powerful "Instagram-type" video recorders available for the iPhone. You can awesomely see what other people have been recording with the iSupr8 app and of course, share your filterized creations to Facebook and Twitter. My favorite feature though? How you can make the viewfinder bigger and actually SEE what you're recording.
iSupr8 used to cost 2 bucks for all this video goodness but is now free thanks to Levi's (for a limited time). [iTunes]