There are three software platforms commonly used to run email lists:
General collections (not marketing oriented) of "lists of lists" can be found at
Other lists of marketing related lists can be found at CyberPulse as well as Kim Bayne's Marketing Lists.
In addition, you might wish to peruse the Statistics list of lists, or Bill Goffe's collection of Economics lists from his Resources for Economists on the Internet.
With all of these lists to keep track of, you can get help subscribing and unsubscribing at http://www.listtool.com/.