Arduino enthusiasts of the Apple persuasion have found that there is no direct way to control an Arduino with live keystroke commands as Applescript doesn't provide a way to detect keyboard strokes. However Martin Koch has described a way of doing so, using the "Terminal" application included with OS X and the with the UNIX screen command which allows communication with the serial port.
An interesting work-around for the Apple users out there. For more information and a demonstration sketch, click here. And we're on twitter and Google+, so follow us for news and product updates as well.
If you're looking for a simple way of controlling and receiving visual data from an Arduino, consider the Freetronics LCD & Keypad shield which contains a bright 16x2 character LCD and five buttons that can be read from only one analog input pin: