Prepware 2014
I used Prepware 2014 to study for my written exam. I found it to be an excellent preparation tool. They use the same questions/answers that are used on the official test. When running in the study-mode, you can select a specific number of questions from each of the subject-categories to create a test that will pop up an explanation of why your answer is wrong (if it is). The course uses the same work book that you'll be using to take the test at the FAA testing site.