Yesterday I mentioned an excellent tutorial on using UICollectionView. UICollectionView is an excellent addition to the iOS 6 SDK, however at this stage you may be forced to pass on using it in order to support older versions of the iOS operating system.
Fortunately, Peter Steinberger, founder of open source projects such as PSStackedView has created a new open source control that can be used as a drop-in replacement for UICollectionView.
The control, PSTCollectionView, provides a 100% compatible API with UICollectionView and can be used as a fallback in order to maintain compatibility with iOS 4.3+.
Not all features are yet supported, but the basics are there, and it should be good for most cases.
You can find PSTCollectionView on Github here.
A great control for maintaining compatibility with users of older iOS versions.