Are the servers working?
Should be, but you'll have to make sure you have the latest version of Minecraft then downgrade to an older version
The new beta version of Minecraft has just been released which obviously causes some issues with multiplay’s servers so here is how to downgrade your client so you can continue playing on the server until a Hey0/Bukkit update is released:
1. Download the “older” version from Fileplay
2. Make sure your client is updated to 1.2 then quit your client
3. Extract this to:
Windows: %appdata%/.minecraft/
Mac: User/Library/Application Support/minecraft
4. Re-open your client and you can now connect to your Multiplay server!
http://www.fileplay.net/file/12487/minecraft-1-1-client