24 calendar months like all the writtens. Sheppardair is your best bet. It's 75 dollars and they have some sort of deal that you'll get your money back if you don't score above a 90.

http://www.sheppardair.com/trainingaids.htm

You could always just buy the Gleim Book and Study. I know it's a bit old fashioned but it's cheap and effective. :D

well i signed up to do the all ATP's deal on sat in daytona. everyone has been telling me that it will be pretty easy after cramming the 550 or so questions. i am looking through the book to help prepare but dont have any 121 experience. will that be a factor?

contact sheppard air... http://www.sheppardair.com/
download their softward, pay the $75...
I studied it for about a 3-4 days, a few hours a night...94%.