CatechizeMe is a useful tool that helps you learn/memorize the Westminster Shorter and Larger Catechisms and the Heidelberg Catechism. It will be coming soon to the iPhone (they’re looking for beta testers) and they also have a Google widget which has a nice large font size so you’ll notice it on your home page (I put all three of them on my home page) so you’ll have no excuses for not knowing the Catechisms.