Filming is currently underway for the 2010 Doctor Who Christmas special as well as Series 6.
On the British talk show The One Show a few weeks ago, Matt Smith and Karen Gillan were present as guests and this photograph from the filming was shown as well. I guess this confirms what many people were worried about: Yes, there will indeed be snow in this year’s special.
In all seriousness I’ve been seeing reports that the Doctor and Amy Pond will be beseiged by a Flying Shark in this year’s special. Sounds phenomenal to me.