Having a bit of jealousy trouble!?

I met this boy shortly before school ended, and we've become quite good friends. We talk nearly every day. Today, this other girl I know started chatting him up and he told me he thinks she's cute. And the most appalling thing happened. I got SO jealous! If I'm getting jealous every time a pretty girl talks to him, that's a sign right? Do I have a crush on him? I think I might. If I do, or even if I don't, what do I do about the envy?