It allows you to simulate analog circuits, LCDs, stepper and servo motors and can include programmable PIC or AVR (including Arduino) processors in your simulation.

If you've mastered the art of Arduino, but haven't yet been brave enough to toss in a bit of GSM communication, the how-to guides linked below definitely deserve your attention.

Arduino devices have had the option of a GSM linkup for awhile, but getting that cellular link to truly strut its stuff hasn't always been easy, even for those of us who'd be inclined to program ...