Hi Gretchen,
Yes,
Mickey's Not-So-Scary Halloween Party dates will be released sometime this spring or summer. Historically it is offered on most Tuesdays and Fridays and occasional Sundays in late September. During October is typically offered more frequently. For comparison sake, these were the 2012 dates that you can use to match up against an online calendar. Keep in mind that it may vary significantly this year.
2012 Dates
--September 11, 14, 18, 21, 25, 28 & 30
-- October 4, 5, 8, 11, 12, 14, 16, 18, 21, 23, 25, 26, 28, 30 and 31
-- November 2
Spirit of Aloha dates will be released approximately 6 months before your visit.
Hope this helps and have a wonderful vacation,
Kaylene