I have a website where people can upload 30+mb of data in a single block, and I want to be able to show them the progress of their upload without causing the web page to become unresponsive, similar to how flash uploads work in gmail.

There's this question here, but I don't know if that progress bar is embedded in the page or if it's using the browser's progress bar. I'm also a bit of a web newb, so I'm not sure if it's the 'easiest'. I asked the swfupload guys how to do this here, and the answer I got is 'this tool requires some knowledge to use it' without giving me much help in figuring out where to get started. I also asked this question on ServerFault, and got no response, so maybe that was the wrong place to ask.

I'm all for learning new things and so forth, but there are a lot of potential pathways to take here. Where should I start, and what do I need to know to make everything work with sinatra, haml, ruby, passenger, and nginx?

Thanks!