Help with moing with mouse!

Ok I need help with something to do with mouse clicks. I want my character (Movieclip) to move where my mouse clicks.
Code:

onClipEvent (mouseDown) {
 endX = _root._xmouse;
 endY = _root._ymouse;
}
onClipEvent (enterFrame) {
 _x += (endX-_x)/speed;
 _y += (endY-_y)/speed;
}

But when ever I click somewhere my character will act as if there is no friction so it starts fast slows down and goes past my click! What is worng?
I also would like to know how to make that object stop when it hits a certain object but cant do it can anyone help me?