Best way to scroll a webpage?

So i’m making this site http://www.rekererreker.no/ (yeah, i know the design looks stupid) and i want the entire site to be in just one html document with the entire laout repeating for every subpage. I’ll use anchors for navigating. The concept of this design is that it is an underwater kinda thing where you go deeper and deeper and eventually ending at the bottom of the sea. I’m gonna add a lot of stuff to the background, fish, bubble and small easter eggs maybe. You’ll have to test this to understand what i want.

Anyways, i’m wondering what will be the best way to animate the scrolling? so that i smoothly scroll deeper down to the bottom instead of just bumping. Some jQuery, mootols or something would do it i guess. Any tips?