Hi Angie,
What a fun time of the year to be at the Walt Disney World Resorts! I have been on vacation at Walt Disney World during this time and it was a fun and crowded experience!
If you are going to be in any of the four theme parks, you can use a standard park ticket to get into the festivities. My family celebrated in Magic Kingdom one year and it was closed early because it reached capacity. We viewed the fireworks from Frontierland as it was less crowded than Main Street. If you are going to choose this park, I recommend getting there by dinner time so you can guarantee admittance.
Another park I have heard good things about is Epcot because all of the countries celebrate the New Year in a different way. While this park has more capacity, I still recommend getting to it early so you can grab a seat around World Showcase.
If you do not want to be in a park, I would say try the beach at Walt Disney's Polynesian Village Resort. I viewed the test show for this year's event on the beach. I have to say it might be my favorite spot as I had a great view of the fireworks and could hear all the music like I was in Magic Kingdom. No ticket required for this event.
Downtown Disney also has a fun list of activities and you can find additional information about all the events for New Years Eve at the
Disney Parks Blog. The Disney Parks Blog is a great way to find out about all the cool events at Disney.
Wishing you a magical vacation!
Beth