Disney just updated their October 2010 Park Hours. Here are the changes I noticed:
Saturday October 2: Magic Kingdom hours extended to 12am from 11pm; Main Street Electrical Parade added at 10pm
Sunday October 3: Hollywood Studios hours extended to 9pm from 8pm; Fantasmic added at 9:30pm
Thursday October 7: Hollywood Studios hours extended to 10pm from 8pm; Fantasmic added at 9:30pm
Saturday October 9: Magic Kingdom hours extended to 12am from 11pm; Main Street Electrical Parade added at 11pm; Hollywood Studios hours extended to 8pm from 7pm
Sunday October 10: Main Street Electrical Parade added at 11pm; Hollywood Studios Hours extended to 9pm from 7pm; Fantasmic added at 7:30pm and 9pm (there were no shows previously scheduled on this date)
Tuesday October 12: Hollywood Studios hours extended to 9pm from 7:30pm; Fantasmic added at 9pm
Thursday October 14: Hollywood Studios hours extended to 9pm from 7:30pm; Fantasmic added at 9pm
Saturday October 16: Magic Kingdom hours extended to 12am from 11pm; Main Street Electrical Parade added at 11pm
Monday October 18: Hollywood Studios hours extended to 9pm from 7:30pm; Fantasmic added at 9pm
Thursday October 21: Hollywood Studios hours extended to 9pm from 7:30pm; Fantasmic added at 9pm
Saturday October 23: Magic Kingdom hours extended to 12am from 11pm; Main Street Electrical Parade added at 11pm
Sunday October 24: Hollywood Studios hours extended to 9pm from 7:30pm; Fantasmic added at 9pm
Thursday October 28: Hollywood Studios hours extended to 9pm from 7:30pm; Fantasmic added at 9pm
Saturday October 30: Magic Kingdom hours extended to 12am from 9pm; Main Street Electrical Parade added at 10pm
A second Fantasmic(!) was added on nights when a first Fantasmic was scheduled except on October 31 when only one show is scheduled at 7:30pm. Two Fantasmics were added on Sunday October 10th. Hollywood Studios hours are also longer on days when Fantasmic is scheduled to accomodate the second show. Magic Kingdoms hours are one hour longer on Saturdays except on October 30th when they are three hours longer. A second Main Street Electrical Parade was added on Saturdays.
These updates were taken from the Disney World Travel Agents calendar that is almost always updated before Disneys own website. The calendar for October is available at
http://www.disneytravelagents.com/S.../pdf/ParkHours/WDW_Operating_Calendar_oct.pdf.