http://www.zoottle.com/ does this, but gives you more control and is not limited to facebook login of course. It also gives you detailed stats (I didn't see any mention of getting visitor stats by FB wifi).
The fact that their plans appear include a certain number of Facebook likes seems very sketchy. However, I'll give them the benefit of the doubt and just assume that this number is the number of users who are given the option to like your page.