Page vertically scrolable when resizing browser

Hi

I have two problems regarding the CSS of my theme. I'm using Friendselectric.
1. I have defined 3 parallel regions in my node.tpl.php and have styled them a bit but as I'm only just beginning to grasp CSS I think I'm missing something as the right region overlaps the middle one. Here is the code. Where am I going wrong?

div.leftfloat {
float: left;
position: relative;
left: 10px;
width: 200px;
top: 10px;
}

div.rightfloat {
float: right;
position: relative;
right: 10px;
width: 200px;
top: 10px;
}

div.middlefloat {
float: left;
position: relative;
left: 100px;
right:10px;
width: 200px;
top: 10px;
}

1. In IE the whole page becomes vertically scrolable, and everything gets "squashed" into the window if I resize the browser.

Thanks. Probably my questions are very beginner-like, but over the past two weeks I've been learning CSS and PHP and playing with Drupal and it's getting a bit overwelming:) Lovin it tho!