I did a little digging into their URL and found these cool dungeon maps. There are some cavern maps too!
I downloaded them all (of course) and then I opened one of them up. Each file has a legend of symbols and then two versions of the map. One that looks more like "stone" and one that is more plain. Both versions of the maps come with or without number keys. See pics below.
PS: if you click on the "Cartography" link at the bottom, you'll find additional map goodness!
PPS: for an "all in one" file, I've put the dungeon and cavern maps together in one pdf file. See the right hand side of my blog.