Domain scheduled password changes

Question?

Does anyone know of a place where I can get written
instructions (white papers) for enforcing end users to
change there passwords every 90 days? I have been tasked
with implementing “User network passwords will be forced
to change every 90 days and require a minimum of eight
characters in length” I?m looking for a little help whereas my
deadline on this project I just received is 20 days away. 😉

Thanks in advance.

please feel free to email me directly at
butch.young@thenationalsystem.com