Just a wee warning first, you site does not center in IE 5.5 and IE 5.0.

Your main navigation does not work at all in IE 5.0, you can't even click through to other pages.

The site is actually quite nice, I like the header, but your logo/name needs to be more effective.

The chunky bevelled headers at the top of each section need to go. Maybe try a more tech background instead?

The navigation buttons would look better if they looked like they were being pressed inwards, rather than just changing colour. Try playing with the bevels/shading on the depressed button to make it look more realistic

Your site is nice and simple, the right navigation is very nice and works in well with the rest of the site.