My questions are:

1. How do I center the banner? (or move it a certain amount of pixles to left/right)
1.b IS this done in CSS or HTML?

2. How do I get rid of the blue part between my banner and my menue? (the banner picture is located in the "header title", the manue is in the "sub header") the code looks like this:

<div id="header">
<h1 class="headerTitle">
<a href="./index" title="Browse to homepage"><IMG SRC="xxx.jpg"></a>
</h1>

<div class="subHeader">
<span class="doNotDisplay">Navigation: </span>
<a href="./index.html">xxxxxx</a> |

2b. is it fixed in html? (if so i can provide the code)

3. How can I make a horizontal space (similar to the right menu)? This is where I would put adds. I want my "content" to always start under it.
3b. html/css?

4. this is my "body" section. where I have recent articles on the front page etc... Is it possible for me to have certain parts split up into a two column format?

I would like to have the option of placing ads/ links/content in both columns. (this would make the site more flexible)
4.b would this be done in html/css?

thanks for the help!

btw that extra blue space above the menue, is considered part of my image banner. ( i cheked my picture in photoshop, and the blue space is not present)

You put your image in the <h1 class="headerTitle"> tags and it looks like you have blue background color for this class
you may want to change it to something like this <div class="logo"> and in your CSS file write something like this:

div.logo
{
text-align: center;
height: 90px; (put exact height of your image here)
}