CraftBukkit has been updated to 1.1 with version #1713 however its not a recommended build just quite yet, meaning still bugs and such, hopefuly (please...) wont be long.

In other news.... thanks to Murasna's suggestion of a flat world, YAMS will not be moving to a flat world! Life is so much easier when things are flat!

i vote new world is totaly flat in the arc feb move to a new land 
Ok just kidding too!

but yeah Murasna, I dont think the terrain will ever be finished well not any time soon anyway, I know Jeb said maybe he should look at backing terrains backwards version combatible but how many things have Mojang said and havent deliverd to date yet? We cant wait for them and be waiting a very long time... or we could go ahead and just pick a map in Feb and then the very next day they could change the terrrain again... it's all luck. Thats why we are just going to have to go ahead with something and hope for the best.
I dont mind not having new biomes and materials in the new world if it changes again becuase we can always use the mining world and such. The only thing that will anoy me though is if Mojang do what they did with Creeper Swamp and Highlands and such and make biomes change = snow!
EDIT: Was reading around and noticed this comment.
@andrewkm Question for you, are 'old' 1.0 swamp-normal borders smoothed in 1.1? or does that only happen with new 1.1 generated maps? Im not entirely sure to be honest. Ive only really checked //chunk //regen with WG and it seems like the old map is totally compatible with 1.1
If that is the case thats a bonus! I may download the mining world which is 1.0 terrain and try it on a test build of bukkit 1.1 and regenerate exsisting areas and see if they change... Ohh and before anyone says anything yes I probably will regenrate the mining world for this update if you are nice to me! Please send cookies and diamonds to "4 Spawn Road, Spawn Town, YAMS."