Interesting article on How to make users scroll down your page.
The size of the page they demonstrate is impressive – 19 feet tall!
Turns out that it's important to make it clear that the page isn't over at the fold, and they show a few techniques for encouring users to scroll – such as avoiding horizontal elements that might indicate that the page is over, using a background for the sides, and others.
They also point you to tools to see how far your users are actually scrolling down, such as Clicktale.