The color, style, and usability are all great. Two things though:
I didnt know what the faces at the bottom mean until I clicked them. I dont think the faces should be changed, but maybe just a quick, "Hey, tap on this face if you don't know, or this face if you don't know and want to ask this question to someone else" at the app's first run.
Also, in my opinion, the "Please Wait..." should be replaced by "Loading..." Everyone know things have to load, but telling someone to wait makes them think that it is slow.
Good job making the app. It looks good, it is an interesting idea, but I'm not sure it's enough to keep people hooked though. I think it's a great platform to keep building on.
Edit: You should probably put the United States at the very top of the list if you think most users are going to want to select that.