Some tips for your XHTML...
Change your links to a <ul> then display:inline through the CSS along with adding any additional styling you desire.
No need to wrap the image in a div there for several reasons... If you want to apply styles to a solitary image you can give the image itself an id or class... if you want to apply the styles to every image on the page just apply them to img {blah} in your stylesheet. If you are going to include an image in the page like that remember to add alt and title tags. Alternatively consider image replacement, applying the image through the CSS.
Instead of wrapping your header text in <strong> tags and ending with a line-break use h1, h2 etc. You can adjust the bottom margin to a negative value if you want to pull the text that follows up a bit to keep your layout.
There's a couple of other things and I haven't even looked at your stylesheet but these are just a few pointers to get you thinking