How do I add ads before my Posts?

Hi
I am new to wordpress – just did my first site using Pinboard.

I will be offering advertising space – so far I have set up ad rotate(square ads) – but I wanted something that moves automatically instead of just when the page is refreshed so I added a slideshow widget as well.(vertical rectangular ads)

I want to offer my clients ads space before the articles in Posts – but dont want it to look like this:
http://www.messageboardcreations.com/?p=906
or even on Pages (at the bottom)
http://www.messageboardcreations.com/?page_id=796

I want it to be separate how can I do that and not have it in the text area or even below my title. (I am not very good with HTML or CSS and I dont know php – HELP!)

Thanks!