You might also find it useful to take a look at Bitlash, http://bitlash.net -- Bitlash is a shell language interpreter that runs on the Arduino, and it is easily controlled from the PC side by typing or sending commands through the virtual serial port. You can store macros in EEPROM to automate small applications.
Download and doc at http://bitlash.net, and some application thoughts on my blog at http://entropymouse.com
Happy hacking,
-br