Minecraft Plus is not a version of the popular Minecraft game, but a standalone guide to the Minecraft world for the iPhone and iPad. Minecraft Plus is available from iTunes and several other Web sites, and is easy to install.
At its heart, Minecraft Plus is a reference guide. Every item and potion, armor, mob, or construction tool in the game is referenced in Minecraft Plus. You can enter what you're looking for in the search engine and pull up all references to that item in the guide. This is not a replacement for the game, but an add-on utility that devotees of Minecraft can use to learn more about the game and its gameplay. There's a good set of tutorials and FAQs to help newcomers to the game, as well as some information on basic gameplay processes such as farming and mining.
Thanks to the popularity of Minecraft, there are several reference guide apps for the iPhone and iPad available. Most have much the same information, so the one for you depends on the interface and how you want to use the app. We like the tutorials and FAQs in Minecraft Plus, which make this app good for beginners. Using an app like this can help new gamers ramp up faster, but it also provides a good reference for more advanced players encountering rarer objects for the first time.