GuestLock - Make guests read your rules.
Version: v0.1

GuestLock lets you set a message to be shown to guests and a command they must use in order to be able to move. This lets you point them to a rules page or such to find the command they need in order to be able to move.

GuestLock supports language translation: Simply edit the "lang" file to change anything GuestLock says.

GuestLock has been translated into Polish and Dutch:

Download Polish lang file. - Thanks to @TGF
Download Dutch lang file. - Thanks to @jorisk322

If you translate this plugin I would be very grateful if you would send me your lang file so that I may share it with others in this post.

GuestLock uses Bukkit Permissions, so any Bukkit Permissions provider will work with GuestLock.

Features:

Lock guests in place until they use a command.
Configurable command and message

Commands:

Changeable in the config file, will unlock a player when used.
Default is: /ilikethisplugin

Configuration:
By default, GuestLock will create a 'config' file and a 'lang' file on run, the defaults are as such:

#Secret command.
#Wed Aug 17 09:58:43 EDT 2011
secret-command=ilikethisplugin

#Loaclization.
#Wed Aug 17 09:58:43 EDT 2011
find-command=&aGo to &7http\://www.example.com/&amp;a to find the secret command.
command-found=&aYou have successfully registered, have fun.

You need to change the find-command line to point users are your website or rules page, and the secret-command to whatever secret word you want them to have to use to unlock themselves.

Then, for the user, they need only use /<secretword> in-game to unlock themselves.

GuestLock was suggested by @Nipper