I would go with the canon t3 over the d3100. It can shoot a ev bracket. The d3100 does not. Also the af is better as well. For pure entry the canon gives you more.
Super Frequent Flyer, no joke. Ex Patriot and loving it.
Canon Eos 60D, T1i/500D, Eos1, Eos 630, Olympus EPL-1, and a part time Pentax K-X shooter.