AS tweening

k guys i have a question on how to do something.
I wanna have text get bigger on rollover and back to normal size on rollout.
ive been doing some tutorials but the effect i get is not as good. this is the script im using

on(rollOver){
_root.main._xscale=110;
_root.main._yscale=110;
}
on(rollOut){
_root.main._xscale=100;
_root.main._yscale=100;
}

i gets bigger but is there a way to have it tween? to give it a smoother effect?