I had a task to rip all the email addresses and usernames out of my Active Directory for our client extranet. I thought what a pain, thinking I was going to have to write some app that will use LDAP and query to get Directory objects that I could rip information from. But ta da I found this little diddy that gave me what I wanted. Its not powerfull and is limited to only a few fields, but they are important fields that we all need. Enjoy.

http://confluence.atlassian.com/display/JIRAEXT/How+to+export+a+list+of+users+from+Active+Directory