Over 24 hours and no response? I wish awesome software came with awesome people. sad

After some forum searching I still have a few questions about placing advertisements (vertical banners) at the top of my site. Right above the top of the forum list.

What part of my theme's CSS would I be modifying, and with what code. Thanks a ton smile

http://img339.imageshack.us/img339/3619/adlocation.jpg
Above is the area I would like to have the ad placed in.