I've done some research into server push with javascript and have found the general consensus to be that what I'm looking for lies in the "Comet" design pattern. Are there any good implementations of this pattern built on top of jQuery? If not, are there any good implementations of this pattern at all? And regardless of the answer to those questions, is there any documentation on this pattern from an implementation stand-point?
I wrote the plugin mentioned by Till. The plugin is an implementation of the Bayeux protocol and currently supports long-polling (local server via AJAX) and callback-polling (remote server via XSS). There is a Bayeux implementation for Python called cometd-twisted that I have heard my plugin works with, but I have not verified this. I have tested and verified it works with cometd-jetty and erlycomet which has a jQuery Comet example included. There is more info on my blog and the current code with a basic chat example can be found on its google code page. Hope this info is helpful and feel free to contact me if need any further help with the plugin.