I have mentioned before that my school encourages all teachers to incorporate reading as much as possible. I have a reading requirement in my Spanish classes, of English-language books with cultural content. (Read about it here.)
One of the concerns I have as a teacher, as do most teachers (and parents!), is to have level-appropriate books for all readers. A good way to ensure this is to note the reading levels of the books, and correlate that with the reading levels of the students, (or vice-verse) making sure there is something for everyone.
Literacy Leveler. It allows you to scan the barcode of a book to find out the various reading levels. It includes the Lexile, the DRA level and the GRL. This is a great resource for parents and teachers to help determine the level of a particular book. The app is easy to use and currently costs $4.99 in the iTunes store.