The way I did was I went to OurStage, MyProfile. I clicked Banners and copied the HTML embed code. Then I went to MySpace and edited in "Safe Mode" and updated the MY BIO section with the copied HTML code. That seemed to work for me.

Check out my MySpace page for a sample: http://www.myspace.com/danielpalmer. My banner is there. Message me if you still have troubles. Banners are great promo tool for you (and they look super cool, I think)

-Daniel