It's dirt cheap too -- $1.99 or $2.99, can't remember which. Includes both EF and OF calendars, with links to the readings, the entire Bible in English and Latin, the entire Baltimore Catechism (as well as St. Thomas's Catechism and the entire Summa Theologica), lives of the saints, every prayer you ever heard of, a lot of them with audio so you can listen while you're driving, a complete guide to Confession . . . and on and on and on.
You can also get the Breviary on line, and the entire Liber Usualis with scores and searchable calendar (THAT is pricey by iPhone standards - 24 bucks).