Animating Buttons With Actionscript?

Hey guys, here’s another one I’m having trouble with (no surprise there =P). I picked up a site I half did a long time ago, when I knew a lot less about Flash. Since I knew so little, I made the timeline very dense (ie 100 things on 1 layer lol), so here’s my problem: I have some buttons on there that I’d like to do some rollover animations on, but since the timeline is so dense, if I put a tween on them, it would royally screw everything up. Any way I can do a simple animation (ie gradual alpha or color change), as if it was a tween, except with actionscript? Thanks for any and all help, I really do appreciate it.