If you don't already subscribe to Johnn Four's newsletter and you play roleplaying games you should. There are also frequent articles about cartography and world design elements such as this week's.

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http://www.roleplayingtips.com/index.php

What I thought was really great was that the Cartographer's Guild received a mention from a User Tip.

4. Online Sources Of Maps
From: Bryan Ray (via GMMastery Yahoo Group)

The Dundjinni User Creations forums are a very good source of objects.
http://www.dundjinni.com

RPGMapShare has hundreds of maps of varying quality. And even more objects to populate those maps.
http://www.rpgmapshare.com/

The GM's Apprentice is the host of a massive, organized art collection called the CSUAC. I don't know what that acronym stands for, but it's almost 700 MB worth of art, free of charge.
http://www.gmsapprentice.com/

And, the Cartographers' Guild, where most of the mapmakers are very free to share their work with GMs in need of a good map. Also note that there is a map requests forum there, in case you need something specific and don't mind either waiting a while or paying for it.
http://www.cartographersguild.com
Johnn also has some RSS feeds on his site if you are into those, and all sorts of useful information for gamers in general.