If you know how to use photoshop, rollover buttons are easy to do.
First create the button which you want to appear first, without going over it with the cursor, then save it. On the same button make a gradient from transparent to white, and it will be the one you wish for the rollover button.
Then on dreamweaver, make a rollover button (from the 'common' section click on the small arrow the 'images' and chose 'rollover image', and it asks you for teh original image (which is the first image you created first) and then the rollover image (which you created with the trans. to white gradient)
There you go as easy as that.
If you dont know how to use photoshop, search for free buttons on google, and you have loads of sites, which you can choose from or create one yourself (with your text, type of glow ....)
Post here if you have any difficulties
Regards