From Touringplans.com (Unofficial Guide to WDW):
See http://www.touringplans.com/tp2/UG2_index.php?PageID=44
Cinderella's Holiday Wish
The new nighttime castle-lighting ceremony at the Magic Kingdom will occur nightly beginning Monday (Nov 12) and running through the holiday season. The show is called Cinderella's Holiday Wish.
The show will feature Disney characters on the castle stage as they ask guests to join them in bringing the shimmering lights of the castle to life. The show will occur at 5:45pm every night.
This show is not exclusive to the Mickey's Very Merry Christmas Party, rather it will occur every night of the holiday season. On the nights of Mickey's Very Merry Christmas Party the show will occur at 5:45pm, followed by a 6pm showing of Wishes fireworks, and the park closing to day guests at 7pm as the party begins. Guests with party tickets who want to see the show can begin entering the park before the advertised beginning of the party (7pm) as early as 4pm. A party ticket will be valid for park entry from 4pm until the end of the party - to reinterate, a regular park ticket is not needed to see the show or enter the park after 4pm, as a party ticket will suffice.
On regular park days (those without the Christmas party) the show will also occur at 5:45pm, with a showing of Dream Along with Mickey on the castle stage (which should be stunning with the lighted backdrop) at 6:40pm. Wishes will occur at varying times on those nights.
See http://www.touringplans.com/tp2/UG2_index.php?PageID=44