It's done using Bukkit ChunkGenerators and ChunkPopulators so it's SMP already!
Yes, now i just need to get it working :/
So far:
-Tree patches that randomly generate (Although they arnt stacking i want them to be a little more random like normal trees)
-Random presents get generated (using names of players on the signs. Plus a few i added) These presents also have a random chance of containing a chest with goodies in it.
To come:
-Snowmen roam the landscape.
-Add some larger Christmas type trees.
-Other structures and things to explore.
-Portal access (A snow portal?? that you light to activate?)