Three Yr Old Behavior

[SimpleMom]

Is there a resource any of you are aware of that I could refer to for behaviors? I have a three-almost 4 yr old that is really active--in a sense. They are very impulsive, sensitive, love toys that make noise (more than others), can't seem to sit still--ever. Very sweet little one, but at the same time ends up hurting someone (i.e. a toy is thrown and someone intercepts it so-to-speak). It's been going on for over a year and a half. Hasn't grown out of the phase. I have taken proactive approaches and the parent's and I have been working together on the issue. It's not a term ordeal, just wanted to get some ideas as to what might be going on and how else to work with them.