Minecraft 1.2.4
We're running it.
Also, to avoid nasty things like sheer cliffs and mismatched biomes, the current world will not be expanded or altered in any way to compensate for new the new biome, Jungles. Instead, I've added a small world which is exlusively Jungle biome. All the trees, green, and cats anyone could ever want.
Currently, the warp to it is /warp jungle.
There will be at least one portal to it soon, once I've constructed an appropriate spawny area.