I asked about this on dizpins and Joette responded with a little more info. That it would cost $99 pp to go. Includes dinner. Just so happens I'll be on vacation during that time, so will add this to my things to do while there. I would rather do this then the Halloween Party. Can't wait to find out more.
Here's the info from the thread from dizpins.
That is for WDW...and Disney is just giving you a little teaser...
However...the unconfirmed rumors are that...
Walt Disney World is hosting a Haunted Mansion event this Halloween (October 30, actually.) The event will cost $109.99 per guest (with a 9.99% discount to AP holders.) It'll take place from 8 pm till the stroke of midnight on October 30, 2002. The evening will include a delightfully ghoulish buffet dinner, as well as a chance to meet your favorite characters from the Haunted Mansion. Participants will be limited to a total of 999.
Tentatively scheduled events include early admission to purchase exclusive limited edition merchandise, exclusive souvenirs available only to event participants, a chance to meet and greet the artists of some of the special merchandise and have it signed, exclusive pins, storytelling events, souvenir photos, and more. The Magic Kingdom will be closed to the public, but the surrounding areas of Liberty Square and Frontierland (including the Country Bears, Splash Mountain, Big Thunder Mountain, and of course, our Haunted Mansion) will be open for event participants to enjoy. And, of course, the event won't be complete without a trip through the Haunted Mansion, which promises a few eerie surprises of its own for this special evening.