I couldn't find the 2008 info either, but the 2007 info is there. You should be able to estimate the 2008 dates by looking at the 2007 info. Blackout dates are around major Holidays.
Once you are logged in, click on Member Privileges, then Member Perks, Walt Disney World Resort, Recreation, and finally, Water Activities. Then scroll down to the Pool Hopping Info for 2007.