Nikon d3100 compared to nikon d90?

I want to know the major differences between the two slr's. I'm not a professional photographer by any means but I love great quality pictures. I'm trying to figure out which is best for me and delivers good performance.

Added (1). I know that the d3100 can only use certain AF lenses. Will any new lens that comes out be supported by the d3100?

The D90 came out in 2008 and the 3100 came out late last year. The 3100 is better in low-light, high ISO situations and is cheaper. The D90 has a slightly better AF system. The D90 has been replaced by the D7000. If you do buy a D90, BUY A USED ONE! Update - the D3100 can only auto-focus with AF-S lenses. The kit 18-55 is an AF-S model.

Nikon, currently, is pretty much putting out purely AF-S lenses, all of which will work on every DSLR from Nikon

If you don't care about video, the D90 would be the better choice. It is an older camera, but it is a lot nicer to use, especially since it has a second scroll wheel where you can change aperture/shutter speed without having to push a button

D3100. You need AF-S lenses. Most but not all lenses that come out now are AF-S. (or sigma's hsm). D3100 gives you about a stop more useable high iso.video is loads better

D90 you get a motor in the body, you get better controls, option for a grip. You can control nikon flashes wirelessly.

D90 is 3 years old, has worse ISO performance, worse video options. It has better build quality, top LCD screen, larger viewfinder and weighs more.

Image quality is the same. And there are plenty of lenses that will work with D3100 and non AF motor bodies. Take a look at the D5100, I think you'd be better of with it as it's a mix of these two.

Here's a DSLR Buying Guide - http://www.the-dslr-photographer.com/2009/11/which-dslr-to-buy/