They'll ban you if they catch you covering the ads but whatever.
I'm not too familiar with myspace so I can't guarentee this will work without
messing about with it, but divs work kind of like this.
Define your css styles first:
<style type="text/css">
#yourstyle {
Background: #FFFFFF;
border: #00E0FF;
position: absolute;
top:0px;
left:0px;
width:100%;
height:100%;
}
</style>
You can either apply these styles to divs already in use or make your own.
And these are just examples, theres alot of other stuff you can do, you should read up on some css.
Then you'd apply an id to the div to link the css with the div but like I said if you know the ids of myspace's divs already in use you should be able to change them.
<div id="yourstyle"></div>