PART 2 HERE
We go through some raw ins and outs of doing the famed parallax effect. It seems to be a big deal lately.
This is by NO means the only way to do this, but this is the one I like. I use webkit transform instead of margin-top because of performance.
To make this work in all browsers, you need to use all the css3 transforms, and the paul irish request animation polyfill, as well as make a fallback from the transforms to margin-top.