Scandinavian: 2. Nc3 d4 I started out with a simple opening: 1. e4 d5 2. Nc3 and then the computer played 2... d4, surprising me, as I had never encountered it before. Since then, I've been trying to analyse the possible ways to see if I can make this turn in my favor or if it simply means my knight is going to go on a less active square; so I wanted to know what was the best way to counter this move. Please note, I am a casual player trying to get into more intermediate/advanced chess and if you have any programs or online suggestions on teaching me openings I would love to hear them. Thanks.
3.Nce2, followed by Ng3, Nf3, Bc4, O-O, etc. is reasonable. 

A thematic game to reference is http://www.chessgames.com/perl/chessgame?gid=1186636

In general, however, 2.Nc3 isn't known as the best theoretical response.