I have a schedule of events, the ul has a fixed height and overflow hidden, the li's also have a fixed height. Only four are visible at a time. I need to figure out how to scroll through the list, both up and down on click of the appropriate button. 

I'm sure there are plug ins out there that can do this, but for a better understanding of jQuery/JS I want to do this on my own - but need some help. HTML/CSS is here <http://jsfiddle.net/DirtyBirdDesign/BJdJ7/>

I have broken this down into the following needs:

1. Loop through and index the number of list items
2. Get the current position
3. on each click of the 'down' button, move the position -41px
4. on each click of the 'up' button, move the position +41px
5. animate the transition
6. Loop continuously - go from last to first when last is visible

Am I missing anything on the above? How do I go about this?
thanks for the knowledge!