Simple open source regex to detect mobile browsers. Very cool, super useful. Free and open source. Yay!
A really easy to understand intro to html5 and other stuff. Very handy, beautifully written, elegantly presented, a joy of a web page.
Very useful article on offline web apps using HTML5 cache manifests.
Very handy script that might provide a way of using the browser as a proxy. Needs a little investigation to be sure.
BrowserShots is an open source project which allows you to see screenshots of a url in a huge number of browsers across a number of operating systems. Very useful for web site development / testing.