What should I do? Boy question?

I have known this one boy since I was two, and we are good friends. I am also bff's with his sister, who is my age. He is two and half years older than me, but going off to college next fall. We see each other at church almost every week, and tend to hang out together. His sister, him, and I all are good friends with a family that has two kids, 3 and 7, and in the summer we tend to cross paths when we are "mother's helpering" (they have a big property, plus the kids are a handful). He makes me laugh, and seems to like me I guess. We had an encounter when we could have kissed but it didn't happen. When I have gone over to his house to hang with his sister, he will often come in and join in whatever activity we are already doing, but we take it in good stride. His sister and he are very close, almost more like best friends, and not siblings. He's hugged me, asked me about more personal things, and seems to have flirted with me on a couple of occasions. He is single, and I believe he has never dated anyone or had a girl friend. What should I do? Should I make a move, if so, how? And, do you think he likes me? (I don't think his sister would have any problem at all if I were to date her brother; she's an awesome person.)