You can do it using .prev() and .find() or .children(), like this:
$('.btn').prev('h2').find('a').attr('href');
You can give it a try here. The <a> isn't a sibling so .prev() won't won't work, you have to go back to the <h2> which is a sibling, then go inside it to get the <a> itself.
Nick Craver
2010-08-18 19:17:14