DoubleJumpReloaded is another simple DoubleJump plugin for hub servers. However this is the simplist of them all, with a configurable config.yml that allows you to alter the jump height, sound effects, visual effects and message on jump!
Download the most recent version of DoubleJump. Drag it into your plugins folder. Reload your server. And configure the config.yml to your liking! Remember! Default players will need the permission add to their group for it to work for them.
To use DoubleJumpReloaded, once the plugin is in the plugins folder and the permissions have been added, just double tap your spacebar!
Thanks to MCPluginTuts for the tutorial!