If you're prototyping with Arduino-controlled hardware and get frustrated or don't have much time to keep writing test sketches to test the hardware, Webduino might be the answer. Developed by Cooper Maa, it allows simple control of the I/O pins including PWM, input and output modes via a web browser. The Arduino needs to run the firmata sketch, and can update around 50 ms intervals. You'll also need to run Node, NPM and CoffeeScript on the host PC, however the resulting interface is worth it, for example:
For more information and code, 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: