Dauntless Software's GroundSchool Version 5 sets the standard for high quality, time efficient PC-based FAA Knowledge Test Preparation. GroundSchool V5 Features include:

• Can prepare you for most FAA tests (recreational pilot, airplane,
  helicopter, balloon, commercial pilot, instrument rating, CFI, ATP,
  military competence tests, mechanic, flight engineer, etc.)
• Many, many, many training and learning modes and options to
  allow you to personalize your training
• Built-in automated updating of the software via the included Live
  Update utility assures that you never need to worry about not
  having the latest version ever again!
• 'SmartLearn' advanced neural network algorithm tracks your
  progress and identifies trouble questions for you.
• lookup individual or groups of questions using a wide range of
  search criteria
• integrated library of aviation offers everything from PTS
  documents to FAA training publications to aircraft checklists
  and much, much more
• Versatile review screens allow you to view your results in a
  multitude of ways
• Plentiful online, integrated help
• ability to load and save training / testing sessions
• Printouts galore! Print out score reports to show your CFI, a 'book'
  of questions for yourself to study on the road or in bed, etc.
• If you need an instructor's signoff to take a knowledge test, you
  can get one through the software's Online Signoff Service
  24/7/365 (additional charges may apply).