Up until the last few days, the reply would have been 60 days. Since they are apparently revamping the PS procedures, it is now anyone's guess. I have heard both of these scenarios:
1. WDTC guests purchasing a package can reserve 180 days out as of 8/4/03.
2. All resort guests can reserve all restaurants 90 days out as of 8/4/03.
Keep checking the boards to see when Disney makes a definitive answer.