Craftbukkit build 1317 (which is compatible with Minecraft 1.8.1) has been released. We have installed it on all of the basic game servers. If you have a Premium or dedicated server please open a support ticket to have build 1317 installed.
As with all new builds of Minecraft/Craftbukkit backup your world and nether before changing version.
Please let us know if you find any plugins that do not work with build 1317.