I'm new to CSS so I want to make sure I'm setting things up correctly before continuing.. One problem I know of is the flickering issue in IE for the nav icons. Another might be that I'm using too many divs.
For one if you want an exact font size you should use pixels instead of points. Pixels are pretty much the same across all browsers while points can vary from being to big or to small. Something like 11px or 12px with a line-height of 19px should work pretty good. Also in IE 6 for the pc your navigation images jump when you hover over them. The navigation elements seem to work fine in Firefox 1.0 but I haven't had a chance to check any other browsers or platforms.