If you wan’t to play with arduino, and still didn’d buy or is waiting for the shipping, this is for you. Emulare is a very good emulator, and after some adjustments you can use it very easily.
I installed my some months ago, when I started to read about Arduino. The site to download the installation is Emulare at sourceforge.
The only trick you need to know here is to install comm0comm, a driver to emulate serial ports, to connect with emulare and show the monitor. Blink you leds without a breadboard, play with seven segments display, see your Arduino pins in animated mode.
You can really compile and run your basic codes and download to your virtual Arduino!