What's the difference in d3200 and d3100?

I want to get a Nikon d3200 because it's the camera I'm most comfortable using, and I know my way around it. They're a bit expensive for my liking. However, I found a Nikon d3100 for a much better price. Is there much of a difference between the two? I don't want to purchase a camera I won't know how to use.

If you can operate a D3200, you can operate a D3100 with little or no learning. This site lists the differences between the cameras and calls them "advantages".
http://snapsort.com/...ikon_D3100

Other than some performance issues, all you really lose is the external mic jack.

Well, you picked a great time to get the D3200. It was just announced that after being on the market for nearly 3 years, Nikon has discontinued the model so prices are being cut to clear out existing stock.
It's an old camera by digital standards and you'd be better off with a Pentax K50 than anything in its class by Nikon or Canon.
Here's a side-by-side comparison - http://www.dpreview.com/...pentax_k50

None of the advice here is bad, the D3100 isn't a bad choice at all if your budget is tight, because it's Christmas lots of kids will be getting cameras as presents and not all of them will be chuffed about that, so if you fancy checking out some of the camera buyers guides you will find out about other cameras like the ones Frank mentions and in January when everybody is skint and decides to put all their unwanted stuff on eBay then you might manage to pick up a bargain, if you don't have an eBay account, then chat to a big sister, brother or even mum or dad and tell them your idea, I'd wait until you've made your mind up about the camera you think you'd prefer, and no, the D3100 isn't a bad choice, I'm just trying to help you pick get something that might be better for the money you've got.

Even if you don't get that dream camera, you'll still have enough funds for your D3100, it's a win win, and you'll have learned what patience is.