These topics have been pasted a little too much.
With all seriousness, the most useful place to find 20,000 different answers are:
------------- rAthena -------------
http://rathena.org/board/ (http://rathena.org/board/)
http://rathena.org/wiki/ (http://rathena.org/wiki/)
------------- Hercules -------------
http://herc.ws/board/ (http://herc.ws/board/)
http://herc.ws/wiki/ (http://herc.ws/wiki/)
------------- eAthena -------------
http://www.eathena.ws (http://www.eathena.ws)
http://www.eathena.ws/wiki (http://www.eathena.ws/wiki)