The APH rate is a rate for Annual Passholders. To get this rate all you have to do is call and ask for it and hope it's available. Then you would show your pass at check-in. Right now Florida Resident (FLO) and APH rates are the best. AAA is currently running a special on Annual Passes. Here is the info from their site:
2 Park Annual Pass Special Promotion
11/1/2003 - 2/28/2004 To receive a full year, the passes must be redeemed and photo ID processed on the first visit to the park and no later than April 30, 2004. Members can redeem after that date, but they will not receive a full year, as the clock starts ticking on April 30.