Here is a free plug-in for JIRA that will allow you to manage a backlog within your issue navigator.
In fact, this plug-in provides you tools to order your issues easily (using up and down arrows, and more !).
You can find the documentation and download the plug-in here. (http://www.financeactive.com/pages/pole-dev/jira_issue_orderer_plugin/jira_issue_orderer_plugin_en.jsp
The plug-in is under BSD license, so feel free to use it with no restriction !
This plug-in was created by Finance Active
Finance Active is a French company specialized in Java/J2EE saas applications for financial decision making tools.
You can get more information (if you want to join us for example :-)) about us here. (http://www.financeactive.com/GB-en/Home.do