I don't know of any guides for doing it, but we aren't releasing our code and there's not much we can do but point you in the right direction.
You might want to learn a bit about php and check out the
CURL library or fopen.
Java isn't as common on the web as php or asp. I'm assuming you meant javascript, in which case it is possible to do with javascript and html alone but I'd recommend learning about php for a more stable server-side environment that will work in all browsers.
The high scores cache data in a mysql database and display it using php and html.