Does he like me or not? Sending mixed signals?

I thought the guy I like liked me too. He's always smiling at me and talking to me about weird things (I thought he was making excuses to talk to me), and he sits beside me at lunch when none of his other friends are around. He always seems kind of flustered when he talks to me, like he can't put his words together properly. However, my friend was talking to him, and he said he didn't like anyone... was he fibbing, or is he just sending misleading signals?