It seems like he likes you, I mean, guys usually don't stutter around girls that they don't like. If they do, it probably means he's a bit nervous, and doesn't want to say something stupid around you, because he wants to make a good impression.
If you talk to him on a social networking site and he doesn't reply back, it could be that again, he's nervous about talking to you, and doesn't know what to say, and doesn't want to mess up.
But, the best thing to do is to talk to him in person. Take the initiative to go up to him and strike up a conversation. I'm sure once you break the ice, if he likes you a lot, he'll be willing to continue the conversation. Just make sure you ask him questions that require more than a "Yes" or "No"/"Good" "Bad." Maybe something like: "This weekend went by so fast, but it was nice. What did you do this weekend? Anything fun?"