Bukkit

• Bug fixes
• Some new commands (/ip, /chunk, /lock and /unlock)
• New /ip command to get the IP of a player
• New /chunk command to reload a Chunk if you ended up in a World Hole
• New /lock command to halt server activity (Place and break blocks)
• /unlock command that comes with /lock to disable the /lock features

None that I am currently aware of.