Libraries like these should not be necessary, but since Apple has not implemented proper scrolling of elements and iframes, we're left to do it ourselves. Perhaps iOS 5 (just two weeks until wwdc!) will solve the problem and make this project obsolete (I hope so).

Even if they do, libraries like these may still be necessary for more advanced scrolling mechanisms like those that snap to page boundaries or involve scrolling/zooming hybrids (like photo viewers common to many apps).