I would use a combination of Photoshop and Image Ready. Do your buttons with all the effects of the button states in Photoshop then jump over to Image Ready to do the roll overs, making layers/effects visible or invisible. You can do single buttons or nav bars. Images must be saved as GIF format to have the transparent background. You can also save the html with the code for the buttons and for the preload images. If any of your Photoshop books have a section on Image Ready then that is where you should be looking. Image Ready is for animation, roll overs, image mapping, slicing and optimizing plus more.