Javascript to Jquery

I'm in a bit of a rut. I need to figure out how to convert all this code into jquery. Since I don't know too much jquery. http://www.lastyearsloss.com/store/javascript/map.js I'm not sure which lines I can use or which ones change fully. The main problem is where I'm importing the data from xml. If anyone can point me in the right direction that would be awesome! thanks!