Jakarta project consists tens of sub-projects each with its own mailing lists. The complete mailing lists info page is here. You can search or subscribe to each individual list there. Or, you can browse and cross search all Jakarta lists on this third-party archive hosted by Nabble.
To become a moderator of a mail list:
To learn about moderating a mail list:
Since Apache lists are run by ezmlm, the ezmlm website is a great resource. http://www.ezmlm.org/ezman-0.32/ezman2.html has been very useful for me.