Here's a site comprised of members that are ONLY mithras but also has a neat page for a vanadiel timing clock for things like rse week, moon phases,, elemental days, etc.

http://www.mithrapride.org/vana_time/index.html

The next one is a treasure hunter's map that is an index of just about every coffer/treasure chest map there is.  If you need spawn points here's the place to go:

http://www.speakeasy.org/~sticks/ffxi/treasure/title.html

This next one is the same one posted on this board before, its just the char AF page but neat to look at what your char MIGHT look like:

http://dc1.dawsoncollege.qc.ca/~A332886/

Here's ole' allakhazam and mysterytour, which are pretty much great on general stuff, missions, quests etc.  Mysterytour is translated from the JP version so be prepared for engrish.

http://ffxi.allakhazam.com/

http://mysterytour.web.infoseek.co.jp/ffxi/us/

Here's a fame guide that works sometimes :p

http://ffxi.stratics.com/content/info/fame.php

Lastly, i consider this one a MUST KNOW for ppl like yoshii lol

http://club.pep.ne.jp/~hiroette/en/facemarks/list_index.html

Hope that helps