The Pentagon will announce Friday a three-month timeline for preparing the military to allow gay members to serve openly, Fox News has learned.

Cliff Stanley, undersecretary of Defense for personnel and readiness and Gen. James Cartwright, the vice chairman of the Joint Chiefs of Staff, are expected to lay out a plan that gives the military services roughly three months to train their forces on the new law that allows gays to serve openly in the military, a U.S. official tells Fox News.

The briefers will outline major changes needed in order for the military to smoothly move away from norms associated with the repeal of the Clinton-era legislation commonly known as "don't ask don't tell”...