hello everybody, i have text put into a movieclip ready to scroll ;D

i've been mucking around for ages and cant get the movieclip to scroll automatically to the mouse.

heres my script so far:

onClipEvent(load){
he = 400;
top = 0;
bottom = _height;
}
onClipEvent(enterFrame){
ym = _root._ymouse;
}

of course the top of the movieclip is where the text starts.

basically i want to make it so that the higher the mouse is the faster it moves up until it hits the top, and the lower it is the faster until it hits the bottom.

I have tried stuff and it hasnt been working so please help out

Julian