I would just create a stylesheet with format desired, and populate a 
literal control placed on page with a link to the stylesheet.

Example:
literal1.text = "<LINK rel=""stylesheet"" type=""text/css"" 
href=""../Stylesheets/YourStyleSheet.css"">"




> Is it possible to manipulate (or add) a <style> section in the header 
from 
a>  code?

> I like to add some styles (or generated the complete section) using the 
O> nLoad() function. Is it possible to apply a runat=server? I can create 
a 
i> nstance of WebControls.Style but this isnt realy helpful because I 
cannot 
a> ssign it to the page or header of the page.

> I want to create something the the following:

> <header>...
<> style type = 'text/css'>
 > a {text-decoration:none;}
 > a:hover {text-decoration: underline;}
<> /style>
<> /header>