If you have managed to blink an LED using an Arduino you should be able to easily build this project! ToughRocket52 has put together a fantastic instructable which teaches you how to build your own Arduino controlled disco lights. Not only do these disco lights look fantastic, but you could very easily modify the project to make disco lights in any shape or form! To find out more check out the following link.
If you are looking for an Arduino board to work on this hack why not check out the Freetronics “Eleven” Arduino Compatible Board.
The Eleven is just like an Arduino Uno (and 100% compatible), however the Freetronics team have made a number of improvements to the Arduino Uno design such as adding in a prototyping area, using a micro-USB connector and many more. These improvements mean that the Eleven is as easy to use as possible and is of the highest quality! To find out more about the fantastic Freetronics Eleven check out the following link. The Eleven has just come back into stock so order soon to avoid missing out!