We were there Jan 4-9 this year. There were no crowds at all. Almost everything was a walk-on. Fantasyland was probably the most crowded, and we got fastpasses for a couple of the rides like Peter Pan and Winnie the Pooh, but their stand-by waits weren't long at all. Plus, Fantasyland is always the busiest.
This year, most of the schools started back on Monday, Jan 3. Our schools didn't start back until Jan 10. For 2006, I'm wondering when the schools will start back because Monday is the 2nd.
You don't need to worry about crowds in January, but you do need to worry about the weather. We were very lucky with temps in the 80's. But the week before we were there, and the week after we were there the weather was cold and rainy.
Mary