Go to DIS Discussion Forums - Technical Support. It is very easy to do if you follow their directions.
We will be staying in a 1 BR. I will be there with DH, DS and friend of DS. DS will be 17 so it is nice that he is able to go everyone on his own. We did that this year and it was like a second honeymoon for DH and I. We'll never travel without DS bringing a friend again!
By the way, there was a thread some time ago that suggested when DIS members visit WDW they should put a lime green thread on their door to let other Dis'ers know you are there. I have also read that some people where the ribbon around the parks too.