If I want to have a slide effect between pages. You click a link, it is loaded off to the side and then slides in (pushing the old page off the other side). I can imagine using jQuery to do the PHP and the effects... but how do I do something like this that gracefully degrades for users without Javascript, including bots?

Possibly more problematic: what if I wanted to have a sort of mural background across the site, perhaps with a parallax scrolling effect, and sliding to other pages reveals more of the, possibly giant image?

Again, I can imagine how to do this with lots of fancy jQuery and PHP but it would heavily rely on those. How can I gracefully degrade in a situation like that?

Any pointers, articles or books would be greatly appreciated. I keep trying to search for answers but I just get a lot of "theory"-based, unhelpful blogs.