Lockette allows you to lock your chests and doors simply by placing a sign on them. You can allow other users access simply by adding their names as well.
Yourself only:
Code:
[Private]
YourUsername
You and a friend (two sign style):
Code:
[Private]
YourUsername
Code:
[More Users]
User1
User2
Usage video:
Original Bukkit forums thread:
http://forums.bukkit.org/threads/sec...556-1185.4336/