May i suggest
http://www.w3schools.com/css/default.asp
As for your code... well...
"align: center;" is not valid CSS (as far as i know - IE might muck it up.) and therefore doesn't really do anything - besides which, by absolutely positioning the element you're doing just that - telling exactly where you want the element to be. You might be getting problems from not delcaring a unit for your measurements - try 130px instead of just 130.
-edit- Hibbilty Jibbilty! After a second look i think i know what the problem is. You're having troubles because you've positioned the div within the keen_ad div. When you use position: absolute you measure from the inside of the containing element - in this case the keen ad. By not setting a unit the top and left lines are not being parsed, forcing everything to just sit on top of stuff.
Add px, and unnest your DIVs and everything should work. --
I looked a bit at your page - you seem to have a lot of extranious HTML tags in there like <CENTER> that you really don't need if you're using CSS.
As for putting the style within the element - it is frowned upon because then you're mixing content and presentation - the seperation of which was sort of the point of CSS.