If you mean a world map generator, there's [url=http://donjon.bin.sh/fantasy/world/]this one here[/url]. It's decent if you just want something quick, but it doesn't have many settings for how you'd want your world to look, e.g. number of continents or whatever.

The same site also has a [url=http://donjon.bin.sh/adnd/dungeon/]dungeon generator[/url]. It generates a dungeon map set to your specifications (box, cavernous, rounnd, etc...) and also provides some other useful information, including potential enemies to encounter. 

The site has some other decent generators, but as far as I know, those two are the only ones that actually makes maps.