It didn't come with a map maker, but they just released it. Since you need to register (and patch at this point) the game with Steam, it'll give you the option to download the Modding tools (which includes many, many things).
The map maker is OK. It lets you do most things you need to do and it has an undo key, so I guess that's most things I'd want. I wish it had a mini-map so I could quickly view my progress. I was working on a map of Italy and then realized that I didn't leave enough space up top. So I kinda have to start over.
BTW, here's what I had so far (terrain types not finalized and nothing outside of Italy was finalized). Shame to have to start over again, but I also messed up a few other things.