delete the whole < img > out of your header since you set it as the backround of the header div. Right now it is pushing the menu and title down behind your content.
then in your CSS for #header… remove the two periods leading the location of header.jpg. It should look like “url(/images/header.jpg)” instead of “url(../images/header.jpg)” The periods tell it to step back a directory when it shouldnt (in this case).
thirdly, download the firebug extention for firefox. it will speed up your html/css debugging like you never could have imagined.