BenchPrep aims to help students prepare for those exams by providing test prep. You and/or your students can search through the various courses and see which ones are available for them. Each test provides the source for where the content is added. The AP test in particular come with reading and review material, several practice questions, practice tests, and digital flashcards.
One of the best features, as you can see from the image above, is that BenchPrep makes all the test prep available on iPhones/iPads and Android phones, as well as on the web. By syncing, students will be able to pick up where they leave off when switch devices.
Other features include the ability to bookmark important parts of the reading material, questions, and flashcards. Questions and reading material can be marked by a level of confidence as well. Notes can also be taken for reminders. At the conclusion of a sample test or questions, students will receive a report and analysis of their work as well.
There is a cost involved, but for what it provides, it seems like a good option.