If you are a high school student or the parent of one, check out IntelliVocab for SAT Deluxe Edition for iPhone on the App Store. The app has just been updated to version 1.2. It was designed by MIT students using intelligent methods of personalizing the learning experience.
If you want an app that offers intuitive and interactive vocabulary-based training, check out IntelliVocab for Business. The app offers training in vocabulary words through written and voice-recognition.
A new IntelliVocab app has been released and this time it is geared to study for the SAT exam. IntelliVocab for SAT is a vocabulary-based app that includes over 600 common words, used in competitive exams. There are also practice sessions with customized words based on expertise level.