I have created a framework called Noduino for accessing your Arduino from a web browser with JavaScript. Commands are piped through modern HTML5 WebSockets to a Node.js server application which sends commands to the Arduino with help of the duino framework.
It's more a proof of concept than a real solution for getting things done with Arduino, there is nothing like shifting bits course. But with Noduino you could for example play browser games with an NES controller hooked up to your Arduino, so it's pretty cool indeed.
At the moment there is an example application for blinking LEDs and catching events from buttons. It's more a JavaScript project than a real Arduino one but it's a nice idea to talk about
Have a nice day…
About Noduino: http://semu.github.com/noduino
Sources: GitHub - semu/noduino: JS and Node.js Framework for controlling Arduino over HTML and WebSockets