For web developers looking to interact with Arduino-based hardware directly from web applications using HTML5, Socket.IO and Node.js, check out this new project by Sebastian Müller. Although still only in alpha stage, it's a promising project that's a "proof of concept for Node.js controlling external components over a dynamic web interface using HTML5 WebSockets". At the moment there's digital I/O control and reading pin status - and hopefully more in the future. There's some excellent tutorials and the whole project is published under the MIT license.
So for more information and to get started, check out the project github. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
If you're new to Arduino, the first step is a solid board for your projects - our Freetronics Eleven - the Arduino-Uno compatible with low-profile USB socket, onboard prototyping space and easy to view LEDs: