This map is about three times larger than the regular Civ4 Earth map.
I started off with a regular physical map, cropped it, ran it through the 'spherize' filter (vertical only) in Photoshop to squish the poles and enlarge the equatorial and temperate regions, then adjusted the aspect ratio so it matched that of the Earth map which shipped with Civ4 (124x68 tiles, or about 1.82:1). Downloaded kswoll's map maker (CFC thread here), and used the handy-dandy image trace feature to lay out continents and oceans.
Initial terrain types were placed with the help of the map at Blue Planet Biomes; rivers and elevation info were found at the University of Texas' Perry-Castañeda Library Map Collection. Resource placement and fine-tuning were done in WorldBuilder.
217x119 = 25823 tiles in this map, which makes it about three times larger than the regular Civ4 Earth map.
All 18 standard Civs are present. I would advise removing some before starting a game (by opening the WBS file in notepad and changing the 'PlayableCiv' parameter for each player from 1 to 0), or else your game will slow down really quickly.
Accurate mineral resources were placed with the help of mineral maps found on the USGS' Web site. Incidentally, I didn't come across a lot of stone on those maps so the Cement resource was used in its place.
All other resources (aka the edible ones) were either placed with the help of vegetation and land usage maps provided by the UT site, or dropped on the map more or less arbitrarily (fish).
Barbarian cities have authentic names and locations. Emphasis was given to barbarian placement which would stop some civs from expanding too quickly (Mongols), act as a partial buffer between two civs (Mali and Egypt, India and Persia), or simply to take up space and make it harder to land-grab (Australia, southern Africa).
I don't think there's too many single barb units running around, but the ample amount of unexplored and fog-of-war territory should take care of that, heh.
There's not a whole lot of fish or whales on the map; I couldn't find any good information on major breeding or fishing grounds. Also, I haven't tested too much with any civ that starts in the Americas so the Americans/Incas/Aztec might be excessively strong or weak.