I really like how sites like FogBugz and Facebook offer snappy user interfaces by loading page content asynchronously.
What are some good resources and patterns for applying this to other websites? I am looking for a solution that creates a unique hash URL for each page, preserves history and basic browser functions, and degrades gracefully if JavaScript is not enabled (a great example of this is Facebook).
This blog post is a good start, but it's far from a complete solution/pattern - and any approaches using jQuery would be great.