Installation
Versions < 2.0
Install the plugin by copying the JAR to WEB-INF/lib inside your JIRA web application and restart JIRA.
Version 2.0 and above
Starting with version 2.0, the plugin is a "type TWO" plugin, which means that the plugin can be installed by copying it to jira-home/plugins/installed-plugins or, better yet, from the excellent Atlassian Universal Plugin Manager.