This tutorial will still work for newer versions of Flash, but since it uses ActionScript 2.0 you'll have to select that option when you make a new file.
Yay! I finally finished writing this tutorial after working on it on and off for several months.
This is a tutorial for three kinds of simple buttons on Flash 8 but it's about the same on other versions of Flash.
Simple button pack: [link]
If you don't want to make your own or if you can't seem to figure it out, you can download the button pack there.
If you have any questions, feel free to ask me.