This is not a bad design, but it could do with some improvements.
The first thing I spot when viewing the page, is the 'twhirl' image link in the bottom right corner...it just doesn't look right there.
The typography needs a little work, as all I see in your CSS is two fonts, you could possibly add a third.
On the actual logo, it's hard to read the 'twitter mobile/app search' above the 'wapp finder' text. You could also make the logo a link to the home page.
The bar at the top could be removed, and the link for the 'submit app' could be placed to the right of the logo maybe saying something like 'Have you got an application for Twapp? (next line) Submit it here!' as the empty space on the right of the logo brings the design down.
Your code is
invalid, but it is only 9 errors which can be easily fixed.
Spacing needs a little work, as I see very little consistent spacing below the logo.
Overall, it is a brilliant design but there are little things that bring the design down.
Keep up the good work.
